---
title: "AT89S5253 SPI Problem"
url: "https://maker.wiznet.io/forum/9844"
markdown_url: "https://maker.wiznet.io/forum/9844/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "Seppel"
created: "2014-01-20T18:57:01+09:00"
last_activity: "2017-05-04T08:31:11+09:00"
language: "en"
views: 754
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# AT89S5253 SPI Problem

## Question

Asked by Seppel on 2014-01-20 in Ethernet Chips.

Hello,

I am using an Atmel AT89S8253 MCU with the W5100 controller via SPI.
Although software (bit-banging) SPI does work, I cannot use the integrated hardware SPI of the 89S8253.
I’ve tried all modes, but even mode 0 does not work, reducing the ISP-Speed didn’t work either.
On the other hand, I can drive SD-Cards and a 128x160 TFT-Display at full speed (12Mhz SPI-clock) without any problems in the same circuit.

Has anyone else got similar problems?

Regards,
Roland

## Replies

### Reply 1 by Seppel, 2014-01-21

Hi,
I own a 20 MHz 2-channel analog scope,
but don’t think that I can make good enough pictures of the waves.
What signals would you like to see? Sck vs. Mosi and CS vs. Sck?
Before I used hardeware SPI inside the 89S8253 with SD-Card, display and w5100, I used
only software SPI with an Atmel 89S82 and dicovered that I had to
adjust my SPI routine specially for the w5100. Although all components claim
to expect mode 0. And I programmed mode 0 for SD and display before I tried the w5100.
Since software SPI is quite slow it can’t be a real timing problem.
It is more a problem when each signal has to be asserted in general. (IMHO)
Hat do you think about it ? Can I contact Wiznet about this somehow?
Cheers, Roland

### Reply 2 by Seppel, 2014-01-22

Hi,
I use an Arduino Ethernet-Shield that has an inverter for /CS → SEN.
So the reqs of that AN should be met.
It’s a pity the shield also uses a resistor network for adjusting voltage
to 3.3V, but I have alread checked the voltage levels and waves, which seemed all right to me.
But I am going to check it again…
I used the 00 01 02 03 - scheme writing to the w5100 for debugging of the soft-SPI-routine.
Thanks, Roland

### Reply 3 by Seppel, 2014-02-04

Hi again,
it took me some time , but now I know what went wrong.
I did not reset the W5100 correctly. Strange, it works via software SPI then but
gets the hiccups when I use Hardware SPI.
Thank you for your help!

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Source: https://maker.wiznet.io/forum/9844