ADC Registers Not Updating

[gwilson]

Posted on September 19, 2006 at 15:28

ADC Registers Not Updating

[gwilson]

Posted on September 19, 2006 at 15:08

I am currently using the ST Microelectronics Software Modules to initialize the STR710FZ1 ADC registers and begin polling the data. However, when I view the values in memory through Seehau EMUL-ARM software the ADC->CSR and ADC-CPR registers are not updating.

Also, the reset values for the ADC->CSR register is not 0x0000 and the ADC-CPR contains the same value as ADC->CSR. When I set the memory location 0xE0007020 (CSR register) to 0x0000 the value 0x200F appears instead.

Not sure if this is an issue with the processor or the tools. I am using Microcross GCC compiler and the Nohau EMUL-ARM debugger.

[kleshov]

Posted on September 19, 2006 at 15:28

If you read the reference manual, you will see that ADC_CPR is write-only, a read from this register will return 0.

ADC_CSR holding a value of 0x200F is perfectly understandable. It means that the OVERRUN bit is set and conversion was complete for all four channels. The ADC begins running in round-robin mode emmediately after reset. Unless you read the ADC_CSR within a millisecond or so after reset (before the first conversion is done) you cannot observe the reset value of ADC_CSR which is 0.

Regards,

- mike