Technical Q&A

HW 51 - dl command in 1 machine mode (29-Mar-99)

Q: While working with the Open Firmware user interface in 2 machine mode I use the download word, dl, to debug my code. Recently, I started using 1 machine mode and I executed a word that used the dl command and the machine hung. Control-D would not cause a return to the user interface. Why?

A: The serial interface will send data when given data. If there is no cable connected to another machine, the interface cannot detect this and will hang. However, the dl command is rarely encountered in 1 machine mode so this hang situation should not cause a big problem.