ChipLoad to BCM20736 + new EEPROM

[Anonymous]

Hi,

I'm trying to bring up a new board with a BCM20736 and an empty EEPROM.  I've successfully programmed a commercial dev board directly using ChipLoad and indirectly using "make" on Linux, but no success with our board.

I monitored the UART on the 3rd party dev board and I see data being transmitted and received.  With our board, I see a few bytes being sent to the BCM20736, but nothing coming back.  We've checked power supplies, clocks, and it seems that the I2C bus to the EEPROM is active after reset, so the 20736 seems alive.  My assumption is that the 20736 would fail to run code from the EEPROM and fall back to the code in internal ROM, code that I hope will talk over the UART to ChipLoad.

I have read this post:

Programming the TAG2/TAG3 Board using command line tools

, but it's not clear that ChipLoad will be able to get past an unresponsive UART, unless I'm missing something about how the UART must be connected or the default state of the 20736 with no code in EEPROM.

Any suggestions or additional resources that might shine a light on general board bring up process?

Thanks!,

John

[MichaelF_56]

This thread explains in detail the boot process for the 2073XS: firmware programming through FTDI VCOM 22 to BCM20736S

This part is important since there will be no valid configuration found within your empty EEPROM:

2b.

If no valid configuration was found, the next step depends on whether the HCI_UART RX pin is asserted or not:

• If HCI_UART RX  is asserted, the part enters recovery mode

• If HCI_UART RX  is NOT asserted, the ROM will assume all default configuration settings and then boot up into download mode

In addition, the selection of the correct external FTDI programming cable is critical as well.

Recovery mode is explained in the WICED Smart Quick Start Guide (SDK 2.x and TAG3 Board)​

[Anonymous · Accepted solution]

Our board has HCI UART Rx is pulled high, but it looks like the missing piece was the state of SDA when the chip comes out of reset (/RESET set high).  Adding a button that holds SDA to the EEPROM high similar to the 20736 dev board we have allowed the programming to succeed.

Thanks for your help!,

John