Helmut Schmücker / i2cBugRepro

Reproduce https://mbed.org/forum/bugs-suggestions/topic/4128/ bug in med-NXP

Dependencies:  

main.cpp@0:308c98db9173, 2013-05-19 (annotated)

Committer:
humlet
Date:
Sun May 19 07:15:51 2013 +0000
Revision:
0:308c98db9173
reproduce ; https://mbed.org/forum/bugs-suggestions/topic/4128/

Who changed what in which revision?

UserRevisionLine numberNew contents of line
humlet 0:308c98db9173 1 #include "mbed.h"
humlet 0:308c98db9173 2 #include "I2C.h"
humlet 0:308c98db9173 3
humlet 0:308c98db9173 4 int main()
humlet 0:308c98db9173 5 {
humlet 0:308c98db9173 6 const int len = 128;
humlet 0:308c98db9173 7 char strs[2][len];
humlet 0:308c98db9173 8
humlet 0:308c98db9173 9 I2C i2c(p28, p27);
humlet 0:308c98db9173 10 const uint32_t adr = 0x70<<1;
humlet 0:308c98db9173 11 char rData[5];
humlet 0:308c98db9173 12 char wData[5];
humlet 0:308c98db9173 13
humlet 0:308c98db9173 14 for(int i=0; i<2; i++) {
humlet 0:308c98db9173 15 // read SW rev from register 0x00 from a srf08 ultra sonic ranger at i2c address 0x70/0xe0
humlet 0:308c98db9173 16 wData[0] = 0x00; // register address
humlet 0:308c98db9173 17 int wStat = i2c.write(adr,wData,1,1); // write register address and keep bus open, i.e. don't finish write sequence with an instnt stop condition
humlet 0:308c98db9173 18 if(i)wait_us(23); // grant some time to the i2c HW to start the unintentional additional write
humlet 0:308c98db9173 19 rData[0]=0xff;
humlet 0:308c98db9173 20 int rStat = i2c.read(adr,rData,1); // read srf08's SW rev from register 0x00. If in time, the start condition at the beginning of the sequence would abort the unitended write
humlet 0:308c98db9173 21 snprintf(strs[i],len,"wStat=0x%02X rStat=0x%02X rData=0x%02X %s\n",wStat,rStat,rData[0], ((wStat|rStat)?"OUCH!":"OK!"));
humlet 0:308c98db9173 22 }
humlet 0:308c98db9173 23 printf(strs[0]);
humlet 0:308c98db9173 24 printf(strs[1]);
humlet 0:308c98db9173 25 return 0;
humlet 0:308c98db9173 26 }