I use TNT4882 chip and config it as one chip mode. Firstly continously write command to TNT4882 or read from TNT4882 with agilent VISA function, it works OK. But when use NI 488.2 application, it only can rightly write command to TNT4882 every two times. But can continously read from TNT4882. It is that first write command, it is OK, but second write command, The NI 488.2 return timeout error and TNT4882 can not generate interrupt. I think NI 488.2 does not access bus, So after I finish receive data, I release holdoff and clear STOP. After that, NI 488.2 can successfully write command every time. But when use agilent VISA to contionously write command and read, sometimes missing one byte, So I can not receive right SCPI. I am puzzled that why missing middle byte. For example command is "centerfreq", maybe I only receve "centerreq". When recevie config, I config GPIBDataWrite(TNT_AUXMR,0x96); when send cofig, I config GPIBDataWrite(TNT_AUXMR,0x99); I don't know what happen?
