No response from NHD-5.0-800480FT-CTXL-CTP
Hi,
I'm evaluating an NHD-5.0-800480FT-CTXL-CTP. I'm trying to read the identification address from a STM32F429I-DISC eval board to the 2x10 pin header. I've triple checked my connections.
My SPI clock seen in the screen capture below is running at 250kHz.
I toggle the PD pin low on boot for 30ms. Then I bring the PD pin high for 30ms before I start reading. I'm trying to read 0x302000. The Most Significant bit of the first byte is '1' for a read, so I'm sending 0xB0, 0x20, 0x00, (dummy)0x00. The MOSI sends 0xA5 to push the data out the MISO, but as you can see the MISO stays low.
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MISO -> NHD Pin 4 -> STM32 Pin PC2
MOSI -> NHD Pin 5 -> STM32 Pin PC3
SCK -> NHD Pin 3 -> STM32 Pin PB10
nCS -> NHD Pin 6 -> STM32 Pin PB12 (GPIO Output)
nINT -> NHD Pin 7 -> STM32 Pin PB11 (GPIO Ext. Interrupt Input)
nPD -> NHD Pin 8 -> STM32 Pin PB13 (GPIO Output)
I imagine the NHD FTDI chip is running side nINT is driven high. When I don't have power to the NHD the nINT pin low.
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Hi Steve,
I wanted to get some clarifications on what you are trying to achieve. Are you trying to read the identification of the display?
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I'm trying to read the display ID on boot. I dug around and perhaps the STM32F429I-DISC board may be interfering with communication somehow. The Discovery eval board has a lot of devices connected to the MCU. There are displays and other onboard devices. The PC2 pin is connected to other devices.
I'm going to try a NUCLEO board in a day or two to see if there is a conflict. The NUCLEO board is a bare-bones type of evaluation board.
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I wired in a NUCLEO board and see the same results.
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Here is a Zoomed in capture of the MOSI signals
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I realized that MSBit of the read request should be 0 for a read request, but I'm still receiving 0x00 responses.
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