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 for allocating the flash write functions in FLASH and RAM respectively. By default, flash write functions are placed in RAM on EFM32G and Series 2 devices automatically and that could not be changed. For other devices, flash write functions are placed in FLASH but that could be changed using EM_MSC_RUN_FROM_RAM.
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.
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 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. |
150
of file platform/emlib/inc/em_msc.h
Function Documentation#
MSC_Init#
void MSC_Init (void )
Enables the flash controller for writing.
N/A |
Note
This function must be called before flash operations when AUXHFRCO clock has been changed from a default band.
791
of file platform/emlib/src/em_msc.c
MSC_Deinit#
void MSC_Deinit (void )
Disables the flash controller for writing.
N/A |
842
of file platform/emlib/src/em_msc.c
MSC_ExecConfigSet#
void MSC_ExecConfigSet (MSC_ExecConfig_TypeDef * execConfig)
Set the MSC code execution configuration.
[in] | execConfig | The code execution configuration. |
857
of file platform/emlib/src/em_msc.c
MSC_ErasePage#
MSC_RAMFUNC_DECLARATOR MSC_Status_TypeDef MSC_ErasePage (uint32_t * startAddress)
Erases a page in flash memory.
[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. *
1229
of file platform/emlib/src/em_msc.c
MSC_WriteWord#
MSC_RAMFUNC_DECLARATOR MSC_Status_TypeDef MSC_WriteWord (uint32_t * address, void const * data, uint32_t numBytes)
Writes data to flash memory.
[in] | address | A pointer to the flash word to write to. Must be aligned to words. |
[in] | data | Data to write to flash. |
[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. *
1331
of file platform/emlib/src/em_msc.c
MSC_WriteWordFast#
MSC_RAMFUNC_DECLARATOR MSC_Status_TypeDef MSC_WriteWordFast (uint32_t * address, void const * data, uint32_t numBytes)
Writes data to flash memory.
[in] | address | A pointer to the flash word to write to. Must be aligned to words. |
[in] | data | Data to write to flash. |
[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. *
1378
of file platform/emlib/src/em_msc.c
MSC_MassErase#
SL_RAMFUNC_DECLARATOR MSC_Status_TypeDef MSC_MassErase (void )
Erase the entire Flash in one operation.
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.
1502
of file platform/emlib/src/em_msc.c
MSC_LockGetLocked#
bool MSC_LockGetLocked (void )
Get the status of the MSC register lock.
N/A |
Returns
Boolean true if register lock is applied, false otherwise.
331
of file platform/emlib/inc/em_msc.h
MSC_LockSetLocked#
void MSC_LockSetLocked (void )
Set the MSC register lock to a locked state.
N/A |
348
of file platform/emlib/inc/em_msc.h
MSC_LockSetUnlocked#
void MSC_LockSetUnlocked (void )
Set the MSC register lock to an unlocked state.
N/A |
363
of file platform/emlib/inc/em_msc.h
MSC_ReadCTRLGet#
uint32_t MSC_ReadCTRLGet (void )
Get the current value of the read control register (MSC_READCTRL).
N/A |
Returns
The 32-bit value read from the MSC_READCTRL register.
381
of file platform/emlib/inc/em_msc.h
MSC_ReadCTRLSet#
void MSC_ReadCTRLSet (uint32_t value)
Write a value to the read control register (MSC_READCTRL).
[in] | value | The 32-bit value to write to the MSC_READCTRL register. |
399
of file platform/emlib/inc/em_msc.h
MSC_IntClear#
void MSC_IntClear (uint32_t flags)
Clear one or more pending MSC interrupts.
[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). |
550
of file platform/emlib/inc/em_msc.h
MSC_IntDisable#
void MSC_IntDisable (uint32_t flags)
Disable one or more MSC interrupts.
[in] | flags | MSC interrupt sources to disable. Use a bitwise logic OR combination of valid interrupt flags for the MSC module (MSC_IF_nnn). |
567
of file platform/emlib/inc/em_msc.h
MSC_IntEnable#
void MSC_IntEnable (uint32_t flags)
Enable one or more MSC interrupts.
[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.
589
of file platform/emlib/inc/em_msc.h
MSC_IntGet#
uint32_t MSC_IntGet (void )
Get pending MSC interrupt flags.
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).
609
of file platform/emlib/inc/em_msc.h
MSC_IntGetEnabled#
uint32_t MSC_IntGetEnabled (void )
Get enabled and pending MSC interrupt flags.
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
628
of file platform/emlib/inc/em_msc.h
MSC_IntSet#
void MSC_IntSet (uint32_t flags)
Set one or more pending MSC interrupts from SW.
[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). |
644
of file platform/emlib/inc/em_msc.h
MSC_StartCacheMeasurement#
void MSC_StartCacheMeasurement (void )
Start measuring the cache hit ratio.
N/A |
Starts performance counters. It is defined inline to minimize the impact of this code on the measurement itself.
661
of file platform/emlib/inc/em_msc.h
MSC_GetCacheMeasurement#
int32_t MSC_GetCacheMeasurement (void )
Stop measuring the hit rate.
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.
719
of file platform/emlib/inc/em_msc.h
MSC_FlushCache#
void MSC_FlushCache (void )
Flush contents of instruction cache.
N/A |
750
of file platform/emlib/inc/em_msc.h
MSC_EnableCache#
void MSC_EnableCache (bool enable)
Enable or disable instruction cache functionality.
[in] | enable | Enable instruction cache. Default is on. |
765
of file platform/emlib/inc/em_msc.h
MSC_EnableAutoCacheFlush#
void MSC_EnableAutoCacheFlush (bool enable)
Enable or disable instruction cache flushing when writing to flash.
[in] | enable | Enable automatic cache flushing. Default is on. |
789
of file platform/emlib/inc/em_msc.h
Macro Definition Documentation#
MSC_PROGRAM_TIMEOUT#
#define MSC_PROGRAM_TIMEOUTValue:
10000000UL
Timeout used while waiting for Flash to become ready after a write.
This number indicates the number of iterations to perform before issuing a timeout.
Note
Timeout is set very large (in the order of 100x longer than necessary). This is to avoid any corner case.
128
of file platform/emlib/inc/em_msc.h
MSC_EXECCONFIG_DEFAULT#
#define MSC_EXECCONFIG_DEFAULTValue:
Default MSC ExecConfig initialization.
239
of file platform/emlib/inc/em_msc.h