tom dunigan
Demo of CRC hardware on nucleo F446RE
Revision 0:b154a7908ef1, committed 2016-04-23
- Comitter:
- manitou
- Date:
- Sat Apr 23 00:44:02 2016 +0000
- Commit message:
- demo of CRC hardware
Changed in this revision
| main.cpp | Show annotated file Show diff for this revision Revisions of this file |
| mbed.bld | Show annotated file Show diff for this revision Revisions of this file |
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Sat Apr 23 00:44:02 2016 +0000
@@ -0,0 +1,42 @@
+// test CRC hardware, stupid only 32-bit words, fixed poly
+// CRC32, CRC-32/ADCCP, PKZIP, ETHERNET, 802.3
+// (poly=0x04c11db7 init=0xffffffff refin=true refout=true xorout=0xffffffff check=0xcbf43926)
+#include "mbed.h"
+
+Timer tmr;
+#define BUFSIZE 16384
+
+uint8_t buf[BUFSIZE] __attribute__((aligned(4)));
+
+
+int main() {
+ int i;
+
+ printf("\nSystemCoreClock %d %s %s\n",SystemCoreClock,__TIME__,__DATE__);
+ tmr.start();
+ RCC->AHB1ENR |= RCC_AHB1ENR_CRCEN; // enable CRC
+ for ( i=0; i<BUFSIZE; i++) {
+ buf[i] = (i+1) & 0xff;
+ }
+ while(1) {
+ uint32_t i,us, *p = (uint32_t *)buf;
+
+ CRC->CR = 1; // reset
+ while(CRC->DR != ~0); // wait for reset
+ us = tmr.read_us();
+ for(i=0;i<BUFSIZE/4;i++) CRC->DR = __RBIT(p[i]);
+ us = tmr.read_us() - us;
+ printf("0x%08x %d us ?=0x1271457f\n",~__RBIT(CRC->DR),us);
+ us = __RBIT(0x41414141); // AAAA crc should be 9b0d08f1
+ CRC->CR = 1; //reset
+ while(CRC->DR != ~0); // wait for reset
+ CRC->DR = us;
+ printf("%x 0x%x crc(AAAA)=9b0d08f1\n",CRC->DR,~__RBIT(CRC->DR));
+ CRC->CR = 1; // reset
+ while(CRC->DR != ~0); // wait for reset
+ CRC->DR = 0;
+ printf("0x%x crc(0)=2144df1c\n",~__RBIT(CRC->DR));
+
+ wait(5.0);
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Sat Apr 23 00:44:02 2016 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/082adc85693f \ No newline at end of file