Posted on March 05, 2018 at 17:00Clive,
Thanks for the response.
I would like to get ITM going as it will be useful for debugging during development and i can also use it on production boards without needing an extra connector.
I tried unlocking and setting the ITM directly: (code found in another forum) but no change.
void SWO_Init(uint32_t portBits, uint32_t SysClkHz)
{
uint32_t SWOSpeed = 2000; // 2M baud rate
uint32_t SWOPrescaler = (SysClkHz / SWOSpeed) - 1; // SWOSpeed in Hz, note that cpuCoreFreqHz is expected to be match the CPU core clock
*((volatile unsigned *) 0xE000EDFC) = 0x01000000; // 'Debug Exception and Monitor Control Register (DEMCR)'
*((volatile unsigned *) 0xE0042004) = 0x00000027; //DBGMCU_CR register: Enabling TRACE_IOEN, DBG_STANDBY, DBG_STOP, DBG_SLEEP
*((volatile unsigned *) 0xE00400F0) = 0x00000002; // 'Selected PIN Protocol Register': Select which protocol to use for trace output (2: SWO)
*((volatile unsigned *) 0xE0040010) = SWOPrescaler; // 'Async Clock Prescaler Register'. Scale the baud rate of the asynchronous output
*((volatile unsigned *) 0xE0000FB0) = 0xC5ACCE55; // ITM Lock Access Register, C5ACCE55 enables more write access to Control Register 0xE00 :: 0xFFC
*((volatile unsigned *) 0xE0000E80) = 0x0001000D; // ITM Trace Control Register
*((volatile unsigned *) 0xE0000E40) = 0x0000000F; // ITM Trace Privilege Register
*((volatile unsigned *) 0xE0000E00) = portBits; // ITM Trace Enable Register. Enabled tracing on stimulus ports. One bit per stimulus port.
*((volatile unsigned *) 0xE0001000) = 0x400003FE; // DWT_CTRL
*((volatile unsigned *) 0xE0040304) = 0x00000100; // Formatter and Flush Control Register
}
The fact that i got a few characters in the
'STM32 ST-Link Utility' suggests it should work but I have some setup issue. I keep thinking its clock related but the
SystemCoreClockUpdate() reports the correct core clock frequency.
Chris
