LMX1204EVM: Control LMX1204EVM from AMD ZCU102 (Linux)

Sebastian Held

Part Number: LMX1204EVM
Other Parts Discussed in Thread: LMK04832EVM, , AFE7950EVM, LMX1204, USB2ANY

Tool/software:

Hi,

we've a complex setup with multiple AFE7950EVM, LMK04832EVM, LMX2694EP EVM and LMX1204EVM which need to be controlled from an AMD ZCU102 EvalBoard.

The LMX1204EVM has a built-in USB2ANY circuit, which is directly connected to the SPI channel of the LMX1204. No jumpers to disconnect the MCU from the LMX1204.

There is a SDK for the USB2ANY for Windows, but we need access from Linux (embedded on AMD ZCU102) to the LMX1204.

We need either

1) access to USB2ANY from Linux (preferred)

2) a way to inject external SPI signals without back powering the MCU (through R16, ...) => custom firmware with High-Z SPI

Regards,
Sebastian

3 months ago

0 Noel Fung 3 months ago

TI__Guru* 94300 points

Hi Sebastian,

You can break the USB2ANY connection by removing below resistors.

Then you can connect wires from the following test points to your MCU.

0 Sebastian Held 3 months ago in reply to Noel Fung

Prodigy 10 points

Hi Noel,

Thanks for your quick answer. This solution would work, but we would loose the ability to check/control the chip with TICS Pro. I would really prefer option 1) or 2) from my initial question.

Regards,
Sebastian

0 Noel Fung 3 months ago in reply to Sebastian Held

TI__Guru* 94300 points

Hi Sebastian,

If I remember right, the MSP430 IO resistance is about 100kΩ when Vcc=0V. So it is actually safe that you can connect the SPI interface to your processor without modifying the LMX1204EVM.

0 Sebastian Held 3 months ago in reply to Noel Fung

Prodigy 10 points

Hi Noel,

I don't think that will work. Standard ESD clamping diodes will back feed high-signals to VCC and power the MCU, but I'll try.

Thanks,
Sebastain

0 Noel Fung 3 months ago in reply to Sebastian Held

TI__Guru* 94300 points

Hi Sebastian,

FYI. I tried this on another device, I have connected the SPI of two USB2ANY together, one of them has not power supply. I can read and write register to the device without an issue. SPI speed is 125kHz.

Clock & timing

Clock & timing forum

LMX1204EVM: Control LMX1204EVM from AMD ZCU102 (Linux)