TMP92CZ26A

92CZ26A-64

(3) Description of the USB bo ot program operati on
The boot program l oads a user pr ogram in Intel H ex format se nt from the P C into the
internal RAM. Wh en the user pr ogram has be en loaded succ essful ly, the user program
starts executing from the first address received.
The boot program thus e n abl es users to perform customiz ed on-board progr amming.
a. Operation procedure
1. Connect the USB cable.
2. Set the AM0 and AM1 pins to “1” and reset the microcontroller.
3. After recognizing USB connection, the PC checks the information on the
connected device using the GET_DIS C RIPTOR command.
4. The PC sends the microcontroller information command by control transfer
(vendor request). After the setup stage is completed, the PC checks
microcontroller information data by bulk IN transfer.
5. Upon receiving the microcontroller information command, the boot program
prepares microcontroller information in ASCII code.
6. The PC prepares th e user program t o be loaded by conv erting an Intel Hex file
into binary format.
7. The PC sends the user program transfer start command by control transfer
(vendor request). After th e setup stage is completed, the PC transfers the us er
program by bulk OUT transfer.
8. After the user program has been transferred, the PC waits for about two
seconds and then sends the user program transfer result command by control
transfer (vendor request). After the setup stage is completed, the PC checks
the transfer result by bulk IN transfer.
9. Upon receiving the user program transfer result command, the boot program
prepares the transfer result value to be returned.
10. If the transfer result is other than OK, the boot program enters the error
processing routine and will not automatically recover from it. In this case,
terminate th e de vice driver on the PC and retry from step 2.