LPC MicrocontrollersのトピックRe: LPC5536 - SPI MISO is pulled high by board

LPC5536 - SPI MISO is pulled high by board

fr0stw1ng — Thu, 28 Jul 2022 07:31:35 GMT

Hi, as the title states the MISO pin in multiple connector positions for the HS SPI (SPI8)
are pulled high by board and stay there even after SPI master init is called by all example programs including:
* spi_HS_LSPI_dma_b2b_transfer_master
* spi_polling_b2b_transfer_master

Also tested flexcom2 as SPI without merit.

General result: Misopin is always pulled high from the moment the board is powered.
The pin stays high even after calling SPI_MasterInit() function while other related pins get pulled to their setting. IE CLK, MOSI pulled down and SS stays HIGH untill transfer is started.
This results in miso always being read as 0xFF when reading a byte even when miso pin is disconnected.
Unconnected slave miso shows actual data from the slave device.

See results in Logic analyser below.

2bytes, miso with or without slave connected to miso pin. miso ALWAYS high.2 bytes, miso data read from slave while not connected to LPC5536SPI pins before and after SPI_masterInit()

What am i missing here?
tested an other board with same code without results.

Re: LPC5536 - SPI MISO is pulled high by board

xiangjun_rong — Fri, 29 Jul 2022 02:37:28 GMT

Hi,

As you know that the spi includes 4 signals: /CS, SCK,MOSI and MISO. When the SPI is configured as master, the SCK, /CS and MOSI(master output slave in) are output signals driven by the SPI master, but the MISO(Master input slave output) is an input pin, it should be driven by slave MISO pin so that the master can receive data from slave, because the spi is a duplex interface.

Because the MOSI in master side is an input pin, when the pin is float, it is possible that master receive 0xFF because of internal pull-up resistor. If you connect the MOSI pin with an external pull-down resistor, you will receive 0x00.

Hope it can help you

XiangJun Rong

Re: LPC5536 - SPI MISO is pulled high by board

fr0stw1ng — Mon, 01 Aug 2022 06:58:39 GMT

Hi,

To my knowledge the MISO pin of SPI as master is indeed an input.
Can i asume that you ment MISO in the second half of your post? Since your reply currently states the MOSI is both input and output?

Currently I treated the MISO pin as input and MOSI pin as output in all of my testing.

As seen on the attachements of my previous post, the Mosi pin displays data like its supposed too.
Its the MISO pin that stays high no matter the situation. (always 0xFF)
Even when the miso pin is only connected to a pulldown resistor(10k) I stilll receive 0xFF.
Its almost as if the MISO pin is set as an OUTPUT some how in all SPI example codes while it should be an input.

Checked example codes with 2 different boards with same result, All but MISO functioning on multiple spi interfaces (HS SPI & Flexcom2 as SPI)

Also played arround with the pinsettings in the pins configtool.
I tested the miso pin while specified as following:
Direction :: input, not specified, output
Mode :: inactive, pulldown, pullup
Invert:: disabled, enabled
Opendrain:: disabled, enabled

TLDR : Master In Slave Out stays high even while pulled down by resistor and/or changing available Pins configTool settings.

Re: LPC5536 - SPI MISO is pulled high by board

xiangjun_rong — Mon, 01 Aug 2022 09:42:10 GMT

Hi,

As the following screenshot, the PIO1_3 pin is configured as HS_SPI_MISO function, in other words, when the SPI is configured as master, the PIO1_3 is an input pin, when the SPI is configured as slave, the PIO1_3 is an output pin.

You configured the HS SPI as master, so the PIO1_3 pin function as input, you have to configure the PIO1_3 FUNC bits as 6. BTW, pls try to use 1 K ohm pull-down resistor, then check the data you have received.

Hope it can help you

XiangJun Rong

Re: LPC5536 - SPI MISO is pulled high by board

fr0stw1ng — Mon, 01 Aug 2022 13:27:42 GMT

Hello,

Pin PIO1_3 was already setup as HS_SPI_MISO function with the configtool.
See provided picture.

As you can see the PIO1,3 pin has been setup as input.
In previous post i said that played arround with direction, mode, invert, opendrain settings for the pin as well.

I currently do not understand what you ment by "you have to configure the PIO1_3 FUNC bits as 6."

As for the external resistor, placing a 1k didnt change anything.

Re: LPC5536 - SPI MISO is pulled high by board

xiangjun_rong — Tue, 02 Aug 2022 05:44:44 GMT

Hi,

#define IOCON_PIO_FUNC5 6

//configure the PIO1_3 as HS SPI MISO pin

CLOCK_EnableClock(kCLOCK_Iocon);

const uint32_t port1_pin3_config = (
IOCON_PIO_FUNC6 |
/* No addition pin function */
IOCON_PIO_MODE_INACT |
/* Standard mode, output slew rate control is enabled */
IOCON_PIO_SLEW_STANDARD |
/* Input function is not inverted */
IOCON_PIO_INV_DI |
/* Enables digital function */
IOCON_PIO_DIGITAL_EN |
/* Open drain is disabled */
IOCON_PIO_OPENDRAIN_DI);

IOCON_PinMuxSet(IOCON, 1U, 3U, port1_pin3_config);

Pls add above code in pin_mux.c

Hope it can help you

XiangJun Rong

Re: LPC5536 - SPI MISO is pulled high by board

fr0stw1ng — Tue, 02 Aug 2022 06:37:58 GMT

Hi,

The i found the following in pinmux already.

Regardless I tried replacing and adding both resulting in only the chipselect functioning, no more clock or MOSI and the MISO still high.

Note that i changed the provided function in your code IOCON_PIO_FUNC6 to IOCON_PIO_FUNC(6) since the function IOCON_PIO_FUNC6 was not found by IDE.

i've attached pin_mux.c for you.

Re: LPC5536 - SPI MISO is pulled high by board

xiangjun_rong — Wed, 03 Aug 2022 07:41:10 GMT

Hi,

Because the bridge chip LPC55S69 also can communicate with the HS SPI, you have to disable the U24 by close the JP57 so that the HW_VER_2 node signal is low.

Pls close the JP57 and have a try.

BTW, can you tell us where you connect the PIO1_3 pin to GND via a pull-down resistor?

XiangJun Rong

Re: LPC5536 - SPI MISO is pulled high by board

fr0stw1ng — Wed, 03 Aug 2022 10:44:29 GMT

Hi,

This whole time i thought i posted which board im working on....
The Board is: LPC5536-EVK.

The pulldown resistor is connected to ground on JP8 and the other end is currently only connected to the miso connection on JP7(PIO1_3) and a logic analyser.

I've bridged JP57 didnt result in any changes on the misopin.

Re: LPC5536 - SPI MISO is pulled high by board

xiangjun_rong — Thu, 04 Aug 2022 08:15:52 GMT

Hi,

As the following Figure, the P1_3-CAN0_RD-PDM_DATA1-HS_SPI_MISO is hardware connected to CAN0_RXD via JP48 which is driven by the CAN transceiver.

I suggest you cut the line of the JP48 and have a try

XiangJun Rong

Re: LPC5536 - SPI MISO is pulled high by board

fr0stw1ng — Mon, 08 Aug 2022 06:30:19 GMT

Hi,

Disconnecting JP48 resulted in miso still being driven high.

As a test i've imported another example code and modded its contents to drive the PIO1_3
parallel to the led, stays high here too. whilst the led blinks as needed.
-Pin was set as output in with pins configtool, verified setting in pin_mux.c
-Signal stays high with pin connected or disconnected.
-Output was still pulled down by a resistor to ground.

TLDR:
PIO1_3 stays high while set as GPIO Input, GPIO Output , MISO input
JP48 has no effect.

Re: LPC5536 - SPI MISO is pulled high by board

xiangjun_rong — Mon, 15 Aug 2022 06:10:30 GMT

Hi,

With the following code, I try to toggle the P1_3 based ion LPC5536-EVK board, I can toggle the P1_3 pin. I use the LED_blinky example and add the following code.

Hardware configuration.

1)Open pin1&2 of JP48, connect the pin1 of JP48 to scope

2)close the JP57 jumper, note that JP57 jumper is NOT populated, you can connect connect them with a cable or whatever.

Pls have a try.

XiangJuin Rong

#include "fsl_gpio.h"

void P1_3_Toggle(void)
{
CLOCK_EnableClock(kCLOCK_Gpio1);

gpio_pin_config_t P1_3_config = {
.pinDirection = kGPIO_DigitalOutput,
.outputLogic = 0U
};
const uint32_t port1_pin3_config = (/* Pin is configured as PIO1_28 */
IOCON_PIO_FUNC0 |
/* Selects pull-up function */
IOCON_PIO_MODE_PULLUP |
/* Standard mode, output slew rate control is enabled */
IOCON_PIO_SLEW_STANDARD |
/* Input function is not inverted */
IOCON_PIO_INV_DI |
/* Enables digital function */
IOCON_PIO_DIGITAL_EN |
/* Open drain is disabled */
IOCON_PIO_OPENDRAIN_DI);
/* PORT1 PIN28 (coords: 72) is configured as PIO1_28 */
IOCON_PinMuxSet(IOCON, 1, 3, port1_pin3_config);

GPIO_PinInit(GPIO, 1, 3, &P1_3_config);
GPIO_PortToggle(GPIO,1,0x08);
GPIO_PortToggle(GPIO,1,0x08);
GPIO_PortToggle(GPIO,1,0x08);
GPIO_PortToggle(GPIO,1,0x08);
GPIO_PortToggle(GPIO,1,0x08);
GPIO_PortToggle(GPIO,1,0x08);
GPIO_PortToggle(GPIO,1,0x08);
}

Re: LPC5536 - SPI MISO is pulled high by board

fr0stw1ng — Mon, 15 Aug 2022 06:29:46 GMT

Hello,

Thank you for your reply,

the piece of code does not seem to compile..

Using the code below to toggle multiple pins for testing.
Pins: p1,28 p1,29 p1,25 p0,4 all seem to function as a GPIO output.
p1,3 still does not (still high) even while configuring and measuring as described in your post.

kind regards,

/*
* Copyright 2019 NXP
* All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/

#include "pin_mux.h"
#include "board.h"

/*******************************************************************************
* Prototypes
******************************************************************************/

/*******************************************************************************
* Variables
******************************************************************************/
volatile uint32_t g_systickCounter;

/*******************************************************************************
* Code
******************************************************************************/
void SysTick_Handler(void)
{
if (g_systickCounter != 0U)
{
g_systickCounter--;
}
}

void SysTick_DelayTicks(uint32_t n)
{
g_systickCounter = n;
while (g_systickCounter != 0U)
{
}
}

/*!
* @brief Main function
*/
int main(void)
{
/* Init output LED GPIO. */
GPIO_PortInit(GPIO, BOARD_LED_PORT);
// GPIO_PortInit(GPIO, 1u); // io
GPIO_PortInit(GPIO, 0u); // io

/* Board pin init */
BOARD_InitPins();
BOARD_BootClockPLL150M();

/* Set systick reload value to generate 1ms interrupt */
if (SysTick_Config(SystemCoreClock / 1000U))
{
while (1)
{
}
}

while (1)
{
/* Delay 1000 ms */
SysTick_DelayTicks(500U);
GPIO_PortToggle(GPIO, BOARD_LED_PORT, 1u << BOARD_LED_PIN);
GPIO_PortToggle(GPIO, BOARD_LED_PORT, 1u << 3);
GPIO_PortToggle(GPIO, BOARD_LED_PORT, 1u << 29);
GPIO_PortToggle(GPIO, BOARD_LED_PORT, 1u << 25);
GPIO_PortToggle(GPIO, 0, 1u << 4);

}
}

Re: LPC5536 - SPI MISO is pulled high by board

xiangjun_rong — Mon, 15 Aug 2022 06:36:19 GMT

Hi,

I copy all the code here

XiangJun Rong

#include "pin_mux.h"
#include "board.h"
#include "fsl_gpio.h"

/*******************************************************************************
* Definitions
******************************************************************************/
#define BOARD_LED_PORT BOARD_LED_RED_GPIO_PORT
#define BOARD_LED_PIN BOARD_LED_RED_GPIO_PIN
void P1_3_Toggle(void);
/*******************************************************************************
* Prototypes
******************************************************************************/

/*******************************************************************************
* Code
******************************************************************************/
void SysTick_Handler(void)
{
if (g_systickCounter != 0U)
{
g_systickCounter--;
}
}

void SysTick_DelayTicks(uint32_t n)
{
g_systickCounter = n;
while (g_systickCounter != 0U)
{
}
}

/*!
* @brief Main function
*/
int main(void)
{
/* Init output LED GPIO. */
GPIO_PortInit(GPIO, BOARD_LED_PORT);
/* Board pin init */
BOARD_InitPins();
BOARD_BootClockPLL150M();

/* Set systick reload value to generate 1ms interrupt */
if (SysTick_Config(SystemCoreClock / 1000U))
{
while (1)
{
}
}
P1_3_Toggle();
while (1)
{
/* Delay 1000 ms */
SysTick_DelayTicks(1000U);
GPIO_PortToggle(GPIO, BOARD_LED_PORT, 1u << BOARD_LED_PIN);
}
}
void P1_3_Toggle(void)
{
CLOCK_EnableClock(kCLOCK_Gpio1);

Re: LPC5536 - SPI MISO is pulled high by board

fr0stw1ng — Mon, 15 Aug 2022 07:10:19 GMT

Hi,

The code didnt result in any changes.

Kind regards,

Re: LPC5536 - SPI MISO is pulled high by board

xiangjun_rong — Mon, 15 Aug 2022 07:48:08 GMT

Hi,

Set break point at each GPIO_PortToggle(GPIO,1,0x08);, you can see that the pin will toggle when you run step by step while the JP57 is short by cable.
BR

XiangJun Rong

Re: LPC5536 - SPI MISO is pulled high by board

fr0stw1ng — Mon, 15 Aug 2022 08:06:19 GMT

Hello,

Even while stepping through the program theres no activity on P1,3 only high.
Checked while JP57 is shorted and not shorted.
Checked all pins of JP48 just to be safe.
Also tried adding function GPIO_PortToggle(GPIO,1,0x08);
to the while loop of the LED so the pin would toggle along side the led indefinitely.

Stil no signs on life other than a high pin.

kind regards,

Re: LPC5536 - SPI MISO is pulled high by board

xiangjun_rong — Mon, 15 Aug 2022 09:19:20 GMT

Hi,

You said that "Also tried adding function GPIO_PortToggle(GPIO,1,0x08);
to the while loop of the LED so the pin would toggle along side the led indefinitely.", as far as I know that the node "P1_3-CAN0_RD-PDM_DATA1-HS_SPI_MISO" is NOT connected to any LED, can you tell us which LED the node "P1_3-CAN0_RD-PDM_DATA1-HS_SPI_MISO" is connected?

You have to hook the pin1 of JP48 to a oscilloscope so that you can observe the signal.

XiangJun Rong

Re: LPC5536 - SPI MISO is pulled high by board

fr0stw1ng — Mon, 15 Aug 2022 10:17:52 GMT

Hi,

i did not connect an led to p1,3
what i did is add this to line 67, rest of supplied code was unchanged, for the fun of it i also checked without changes to your code, which in this case the change i made should not break the toggle of pin 1,3 ...
expected result: the led on the board & pin 1,3 would change state every 1 second.
actual result: led flashes & pin1,3 stays high.

while (1)
{
/* Delay 1000 ms */
SysTick_DelayTicks(1000U);
GPIO_PortToggle(GPIO, BOARD_LED_PORT, 1u << BOARD_LED_PIN);
GPIO_PortToggle(GPIO,1,0x08);
}

kind regards,

Bonus info:
we just checked the board from unopened and unused board and
even with original code that comes supplied with the board pin1,3 is high while all other SPI related pins are pulled low.

P1,3

Re: LPC5536 - SPI MISO is pulled high by board

fr0stw1ng — Wed, 31 Aug 2022 06:12:24 GMT

I haven't heard back from you i hope everything is going alright!

I do hope you or anyone at NXP can help me resolve this issue.

kind regards,
Quincy Fleuren