MSC - Memory System Controller#
Memory System Controller API.
Contains functions to control the MSC, primarily the Flash. Users can perform Flash memory write and erase operations, as well as optimization of the CPU instruction fetch interface for the application. Available instruction fetch features depends on the MCU or SoC family, but features such as instruction pre-fetch, cache, and configurable branch prediction are typically available.
Note
Flash wait-state configuration is handled by CMU - Clock Management Unit. When core clock configuration is changed by a call to functions such as CMU_ClockSelectSet() or CMU_HFRCOBandSet(), then Flash wait-state configuration is also updated.
MSC resets into a safe state. To initialize the instruction interface to recommended settings:
MSC_ExecConfig_TypeDef execConfig = MSC_EXECCONFIG_DEFAULT;
MSC_ExecConfigSet(&execConfig);
Note
The optimal configuration is highly application dependent. Performance benchmarking is supported by most families. See MSC_StartCacheMeasurement() and MSC_GetCacheMeasurement() for more details.
The flash write and erase runs from RAM on the EFM32G devices. On all other devices the flash write and erase functions run from flash.
Flash erase may add ms of delay to interrupt latency if executing from Flash.
Flash write and erase operations are supported by MSC_WriteWord(), MSC_ErasePage(), and MSC_MassErase(). Mass erase is supported for MCU and SoC families with larger Flash sizes.
Note
MSC_Init() must be called prior to any Flash write or erase operation.
The following steps are necessary to perform a page erase and write:
uint32_t * userDataPage = (uint32_t *) USERDATA_BASE;
uint32_t userData[] = {
0x01020304,
0x05060708
};
MSC_ErasePage(userDataPage);
MSC_WriteWord(userDataPage, userData, sizeof(userData));
Note
The configuration EM_MSC_RUN_FROM_RAM is used to allocate the flash write functions in RAM. By default, flash write functions are placed in RAM on EFM32G and Series 2 devices unless SL_RAMFUNC_DISABLE is defined. For other devices, flash write functions are placed in FLASH by default unless EM_MSC_RUN_FROM_RAM is defined and SL_RAMFUNC_DISABLE is not defined.
Modules#
Enumerations#
Return codes for writing/erasing Flash.
Functions#
Enables the flash controller for writing.
Disables the flash controller for writing.
Set the MSC code execution configuration.
Erases a page in flash memory.
Writes data to flash memory.
Writes data to flash memory.
Writes data from RAM to flash memory using the DMA.
Erase the entire Flash in one operation.
Get the status of the MSC register lock.
Set the MSC register lock to a locked state.
Set the MSC register lock to an unlocked state.
Get the current value of the read control register (MSC_READCTRL).
Write a value to the read control register (MSC_READCTRL).
Clear one or more pending MSC interrupts.
Disable one or more MSC interrupts.
Enable one or more MSC interrupts.
Get pending MSC interrupt flags.
Get enabled and pending MSC interrupt flags.
Set one or more pending MSC interrupts from SW.
Start measuring the cache hit ratio.
Stop measuring the hit rate.
Flush contents of instruction cache.
Enable or disable instruction cache functionality.
Enable or disable instruction cache functionality in IRQs.
Enable or disable instruction cache flushing when writing to flash.
Macros#
Timeout used while waiting for Flash to become ready after a write.
Default MSC ExecConfig initialization.
Enumeration Documentation#
MSC_Status_TypeDef#
MSC_Status_TypeDef
Return codes for writing/erasing Flash.
Enumerator | |
---|---|
mscReturnOk | Flash write/erase successful. |
mscReturnInvalidAddr | Invalid address. |
mscReturnLocked | Flash address is locked. |
mscReturnTimeOut | Timeout while writing to Flash. |
mscReturnUnaligned | Unaligned access to Flash. |
Function Documentation#
MSC_Init#
void MSC_Init (void )
Enables the flash controller for writing.
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
Note
This function must be called before flash operations when AUXHFRCO clock has been changed from a default band.
MSC_Deinit#
void MSC_Deinit (void )
Disables the flash controller for writing.
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
MSC_ExecConfigSet#
void MSC_ExecConfigSet (MSC_ExecConfig_TypeDef * execConfig)
Set the MSC code execution configuration.
Type | Direction | Argument Name | Description |
---|---|---|---|
MSC_ExecConfig_TypeDef * | [in] | execConfig | The code execution configuration. |
MSC_ErasePage#
MSC_RAMFUNC_DECLARATOR MSC_Status_TypeDef MSC_ErasePage (uint32_t * startAddress)
Erases a page in flash memory.
Type | Direction | Argument Name | Description |
---|---|---|---|
uint32_t * | [in] | startAddress | A pointer to the flash page to erase. Must be aligned to the beginning of the page boundary. |
Note
For the Gecko family, it is required to run this function from RAM.
For IAR Embedded Workbench, Simplicity Studio and GCC, this is achieved automatically by using attributes in the function proctype. For Keil uVision IDE, define a section called "ram_code" and place this manually in the project's scatter file.
Returns
Returns the status of erase operation, MSC_Status_TypeDef
* mscReturnOk - The operation completed successfully. * mscReturnInvalidAddr - The operation tried to erase a non-flash area. * mscReturnLocked - The operation tried to erase a locked area of the flash. * mscReturnTimeOut - The operation timed out waiting for the flash operation * to complete. *
MSC_WriteWord#
MSC_RAMFUNC_DECLARATOR MSC_Status_TypeDef MSC_WriteWord (uint32_t * address, void const * data, uint32_t numBytes)
Writes data to flash memory.
Type | Direction | Argument Name | Description |
---|---|---|---|
uint32_t * | [in] | address | A pointer to the flash word to write to. Must be aligned to words. |
void const * | [in] | data | Data to write to flash. |
uint32_t | [in] | numBytes | A number of bytes to write from flash. NB: Must be divisible by four. |
This function is interrupt-safe, but slower than MSC_WriteWordFast(), which writes to flash with interrupts disabled. Write data must be aligned to words and contain a number of bytes that is divisible by four. Note
It is recommended to erase the flash page before performing a write.
For the Gecko family, it is required to run this function from RAM.
For IAR Embedded Workbench, Simplicity Studio and GCC, this is done automatically by using attributes in the function proctype. For Keil uVision IDE, define a section called "ram_code" and place it manually in the project's scatter file.
This function requires a system core clock at 1 MHz or higher.
Returns
Returns the status of the write operation.
* flashReturnOk - The operation completed successfully. * flashReturnInvalidAddr - The operation tried to erase a non-flash area. * flashReturnLocked - The operation tried to erase a locked area of the Flash. * flashReturnTimeOut - The operation timed out waiting for the flash operation * to complete, or the MSC module timed out waiting for the software to write * the next word into the DWORD register. *
MSC_WriteWordFast#
MSC_RAMFUNC_DECLARATOR MSC_Status_TypeDef MSC_WriteWordFast (uint32_t * address, void const * data, uint32_t numBytes)
Writes data to flash memory.
Type | Direction | Argument Name | Description |
---|---|---|---|
uint32_t * | [in] | address | A pointer to the flash word to write to. Must be aligned to words. |
void const * | [in] | data | Data to write to flash. |
uint32_t | [in] | numBytes | A number of bytes to write from the Flash. NB: Must be divisible by four. |
This function is faster than MSC_WriteWord(), but it disables interrupts. Write data must be aligned to words and contain a number of bytes that is divisible by four. Warnings
This function is only available for certain devices.
Note
It is recommended to erase the flash page before performing a write. It is required to run this function from RAM on parts that include a flash write buffer.
For IAR Embedded Workbench, Simplicity Studio and GCC, this is done automatically by using attributes in the function proctype. For Keil uVision IDE, define a section called "ram_code" and place this manually in the project's scatter file.
Returns
Returns the status of the write operation.
* flashReturnOk - The operation completed successfully. * flashReturnInvalidAddr - The operation tried to erase a non-flash area. * flashReturnLocked - The operation tried to erase a locked area of the flash. * flashReturnTimeOut - The operation timed out waiting for flash operation * to complete. Or the MSC timed out waiting for the software to write * the next word into the DWORD register. *
MSC_WriteWordDma#
MSC_Status_TypeDef MSC_WriteWordDma (int ch, uint32_t * address, const void * data, uint32_t numBytes)
Writes data from RAM to flash memory using the DMA.
Type | Direction | Argument Name | Description |
---|---|---|---|
int | [in] | ch | DMA channel to use |
uint32_t * | [in] | address | A pointer to the flash word to write to. Must be aligned to words. |
const void * | [in] | data | Data to write to flash. Note that this argument must be an address in RAM. This function does not support copying data from flash to flash on series-1 devices. Must be aligned to words. |
uint32_t | [in] | numBytes | A number of bytes to write from flash. NB: Must be divisible by four. |
This function uses the LDMA to write data to the internal flash memory. This is the fastest way to write data to the flash and should be used when the application wants to achieve write speeds like they are reported in the datasheet. Note that this function only supports writing data from RAM to flash, it does not support writing data from flash to flash.
Note
This function requires that the LDMA clock is enabled.
Returns
Returns the status of the write operation.
* flashReturnOk - The operation completed successfully. * flashReturnInvalidAddr - The operation tried to erase a non-flash area. *
MSC_MassErase#
SL_RAMFUNC_DECLARATOR MSC_Status_TypeDef MSC_MassErase (void )
Erase the entire Flash in one operation.
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
Note
This command will erase the entire contents of the device. Use with care, both a debug session and all contents of the flash will be lost. The lock bit, MLW will prevent this operation from executing and might prevent a successful mass erase.
Returns
Returns the status of the operation.
MSC_LockGetLocked#
bool MSC_LockGetLocked (void )
Get the status of the MSC register lock.
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
Returns
Boolean true if register lock is applied, false otherwise.
MSC_LockSetLocked#
void MSC_LockSetLocked (void )
Set the MSC register lock to a locked state.
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
MSC_LockSetUnlocked#
void MSC_LockSetUnlocked (void )
Set the MSC register lock to an unlocked state.
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
MSC_ReadCTRLGet#
uint32_t MSC_ReadCTRLGet (void )
Get the current value of the read control register (MSC_READCTRL).
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
Returns
The 32-bit value read from the MSC_READCTRL register.
MSC_ReadCTRLSet#
void MSC_ReadCTRLSet (uint32_t value)
Write a value to the read control register (MSC_READCTRL).
Type | Direction | Argument Name | Description |
---|---|---|---|
uint32_t | [in] | value | The 32-bit value to write to the MSC_READCTRL register. |
MSC_IntClear#
void MSC_IntClear (uint32_t flags)
Clear one or more pending MSC interrupts.
Type | Direction | Argument Name | Description |
---|---|---|---|
uint32_t | [in] | flags | Pending MSC interrupt source to clear. Use a bitwise logic OR combination of valid interrupt flags for the MSC module (MSC_IF_nnn). |
MSC_IntDisable#
void MSC_IntDisable (uint32_t flags)
Disable one or more MSC interrupts.
Type | Direction | Argument Name | Description |
---|---|---|---|
uint32_t | [in] | flags | MSC interrupt sources to disable. Use a bitwise logic OR combination of valid interrupt flags for the MSC module (MSC_IF_nnn). |
MSC_IntEnable#
void MSC_IntEnable (uint32_t flags)
Enable one or more MSC interrupts.
Type | Direction | Argument Name | Description |
---|---|---|---|
uint32_t | [in] | flags | MSC interrupt sources to enable. Use a bitwise logic OR combination of valid interrupt flags for the MSC module (MSC_IF_nnn). |
Note
Depending on the use, a pending interrupt may already be set prior to enabling the interrupt. To ignore a pending interrupt, consider using MSC_IntClear() prior to enabling the interrupt.
MSC_IntGet#
uint32_t MSC_IntGet (void )
Get pending MSC interrupt flags.
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
Note
The event bits are not cleared by the use of this function.
Returns
MSC interrupt sources pending. A bitwise logic OR combination of valid interrupt flags for the MSC module (MSC_IF_nnn).
MSC_IntGetEnabled#
uint32_t MSC_IntGetEnabled (void )
Get enabled and pending MSC interrupt flags.
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
Useful for handling more interrupt sources in the same interrupt handler.
Note
Interrupt flags are not cleared by the use of this function.
Returns
Pending and enabled MSC interrupt sources. The return value is the bitwise AND of
the enabled interrupt sources in MSC_IEN and
the pending interrupt flags MSC_IF
MSC_IntSet#
void MSC_IntSet (uint32_t flags)
Set one or more pending MSC interrupts from SW.
Type | Direction | Argument Name | Description |
---|---|---|---|
uint32_t | [in] | flags | MSC interrupt sources to set to pending. Use a bitwise logic OR combination of valid interrupt flags for the MSC module (MSC_IF_nnn). |
MSC_StartCacheMeasurement#
void MSC_StartCacheMeasurement (void )
Start measuring the cache hit ratio.
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
Starts performance counters. It is defined inline to minimize the impact of this code on the measurement itself.
MSC_GetCacheMeasurement#
int32_t MSC_GetCacheMeasurement (void )
Stop measuring the hit rate.
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
Note
Defined inline to minimize the impact of this code on the measurement itself. Only works for relatively short sections of code. To measure longer sections of code, implement an IRQ Handler for the CHOF and CMOF overflow interrupts. These overflows need to be counted and included in the total. Functions can then be implemented as follows:
* volatile uint32_t hitOverflows * volatile uint32_t missOverflows * * void MSC_IRQHandler(void) * { * uint32_t flags; * flags = MSC->IF; * if (flags & MSC_IF_CHOF) { * MSC->IFC = MSC_IF_CHOF; * hitOverflows++; * } * if (flags & MSC_IF_CMOF) { * MSC->IFC = MSC_IF_CMOF; * missOverflows++; * } * } * * void startPerformanceCounters(void) * { * hitOverflows = 0; * missOverflows = 0; * * MSC_IntEnable(MSC_IF_CHOF | MSC_IF_CMOF); * NVIC_EnableIRQ(MSC_IRQn); * * MSC_StartCacheMeasurement(); * } *
Returns
Returns -1 if there has been no cache accesses. Returns -2 if there has been an overflow in the performance counters. If not, it will return the percentage of hits versus misses.
MSC_FlushCache#
void MSC_FlushCache (void )
Flush contents of instruction cache.
Type | Direction | Argument Name | Description |
---|---|---|---|
void | N/A |
MSC_EnableCache#
void MSC_EnableCache (bool enable)
Enable or disable instruction cache functionality.
Type | Direction | Argument Name | Description |
---|---|---|---|
bool | [in] | enable | Enable instruction cache. Default is on. |
MSC_EnableCacheIRQs#
void MSC_EnableCacheIRQs (bool enable)
Enable or disable instruction cache functionality in IRQs.
Type | Direction | Argument Name | Description |
---|---|---|---|
bool | [in] | enable | Enable instruction cache. Default is on. |
MSC_EnableAutoCacheFlush#
void MSC_EnableAutoCacheFlush (bool enable)
Enable or disable instruction cache flushing when writing to flash.
Type | Direction | Argument Name | Description |
---|---|---|---|
bool | [in] | enable | Enable automatic cache flushing. Default is on. |