Re: [U-Boot] FW: which protocol do I use to send S-record files when using the loads command ?

Dear Jef Mangelschots,

In message AANLkTi=7zuPGN3ES_zqe6Qrwc+akB4S=JnkLNvsssj_T@mail.gmail.com you wrote:

4. I can not get this to work on our system (our U-boot is configured

for 115200 baud). The following explanation is based on my observation. I might be wrong and please correct me if I am: U-boot can not keep up with the incoming text stream while parsing the S-records, i.e. I saw that it processed the first S0-record correctly, but when parsing the next record, it breaks off because the following

It is not exactly _parsing_ the record, but storing the decoded data to it's final destination, which usually includes flash programming cycles.

record contains junk. As far as I can see, this seems to be because the Terminal program keeps sending data when U-boot is busy parsing a received S-record. Even after the S-record parser breaks off, the

Right. We recommend "cu" and setting the CONFIG_LOADS_ECHO option in your board config file, because "cu" appears to implemnt a simple kind of handshake in the form that after sending a line to the target it waits until it receives a line (the echo) back. Without that, you need to insert inter-line delays.

in delays after each character. Unfortunately, Teraterm and many other terminal programs do not allow delays of less than 1 msec. It works for me with a 1 msec delay after each character but at a grueling slow pace. A file of 3 Mbytes takes hours.

Apply better tools. Use for example "expect", which allows fine-graded inter-charatcer and inter-line timings ( see the "send-slow" command). "expect" is also available for Windows, I understand.

6. maybe I can get this to work by making the RX buffer much bigger,

but haven't tried it yet.

This will not help. U-Boot uses polling drivers. When it is programming the flash, it is simply nt listening on the serial port - no matter how big the buffers are.

8. People that use Kermit under Linux seem to have no problem, but I

do not know in what sense their systems differ from mine.

Kermit binary protocol is not only much more eficient than S-Records, but also much more robust nd reliable.

10. The system I work on is a bareboard embedded system using U-boot

to start up. That is why we are trying to use S-record files for uploading new programs, and not the more efficient FTP used in Linux.

So you do have a network interface on your board? Heck, why don;t you use TFTP then???

Best regards,

Wolfgang Denk