P8355 AND TL866CS - Page 1
Forum section: electronics / repair

author: lionelkjh
author_rank: Frequent Contributor
timestamp: February 26, 2017, 08:48:00 am
content: Hello everyone! I have a dead memory (P8355) which I would like to check. I have an eeprom programmer (TL866CS), which I just bought. So my question is: how do I read the contents of my memory to test, (this last one is not listed)? Is there an equivalence ??

author: pelule
author_rank: Frequent Contributor
timestamp: February 26, 2017, 06:55:17 pm
content: Hi,you are sure, it's a memory?AFAIK the p8355 is a peripheral device (PARALLEL IO PORT) from Intel.

author: picburner
author_rank: Frequent Contributor
timestamp: February 26, 2017, 07:21:09 pm
content: P8355 is a very old Intel peripheral IC with 2K mask rom plus 16 I/O in 40 pdip.The only way to read the ROM data with the TL866CS is build an adapter consulting the Intel datasheet.One little difficulty in the adapter implementation is due to multiplexed data D0-D7 with address A0-A7.

author: pelule
author_rank: Frequent Contributor
timestamp: February 26, 2017, 08:27:06 pm
content: Yepp, picburner is right for the part.If, as lionelkjh posted, the P6355 is "dead", I am not very optimistic, any tool is able to read-out the 2k mask rom data.If it is NOT dead, one may build a a small program for a pic or arduino to read out.

author: eblc1388
author_rank: Frequent Contributor
timestamp: February 27, 2017, 01:47:45 am
content: You can make up an adaptor and select the part AT89C51 in TL866CS to read out the chip.The following image shows the connections that is required. e.g. A wire is required from 8355 pin 9 to the pin17 of the TL866CS programmer. A wire from 8355 pin 11 into TL866CS socket pin 30 and the same for the rest. The number on the arrow indicates how many wires is/are required. Hope this help.

author: lionelkjh
author_rank: Frequent Contributor
timestamp: February 27, 2017, 05:18:10 pm
content: Good evening, I do not know for the moment if the eprom is dead because I have not tested yet because of time and information because it dates from 1980. Cdt

author: janoc
author_rank: Super Contributor
timestamp: February 27, 2017, 05:55:02 pm
content: Quote from: pelule on February 26, 2017, 06:55:17 pmThat would be an 8255 not 8355.

author: pelule
author_rank: Frequent Contributor
timestamp: February 27, 2017, 06:45:52 pm
content: To agree on the P8355 function, see the data sheet (5V, 40pin DIP, 2kx8 ROM, 2x 8bit gen purpose I/O ports).http://www.datasheets360.com/pdf/9215013057629222599Those P8_55 (8155, 8255, 8355) parts where used to build small (low chip count) MCU boards.The 2kx8 memory is a ROM (Mask-ROM), means the data is fix and defined during the production process (the detailed process is not dokumented).So it's no PROM, no EPROM, no UVPROM or EEPROM, it can't be programmed nor erased by the user. So replacing that chip with another P8355 (offered at the bay /http://www.ebay.de/itm/P8355-8355-Intel-I-O-Port-Circuit-2k-Bytes-of-ROM-/200739236265) makes no sense. That parts to buy makes sense only, if (like in the offer) its a replacement part (HP 1820-2295).

author: Rasz
author_rank: Super Contributor
timestamp: February 28, 2017, 08:36:30 am
content: as long as its readable one could bodge something in +8255 as a replacement.

author: james_s
author_rank: Super Contributor
timestamp: March 03, 2017, 08:05:14 pm
content: The multiplexed pins are going to be the biggest pain, I don't know if the TL866 has any supported parts like that.It should be relatively simple to whip up some arduino code that will read it. Heck if you've got a lot of time on your hands you could read it manually with some dip switches and LEDs on a breadboard but that would be tedious to say the least.

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 04, 2017, 11:40:11 am
content: Hello; The P8355 memory is connected to the P8035L microprocessor; I noticed that the latter was heating up. I therefore isolated the microprocessor and I powered the latter with a laboratory power supply without components around. To my surprise, its consumption is 50mA (consumption identical when it is on its support) and heats in the same way: what seems to me a lot. I think he's dead ... What do you think

author: janoc
author_rank: Super Contributor
timestamp: March 04, 2017, 02:34:17 pm
content: Quote from: lionelkjh on March 04, 2017, 11:40:11 amThat is pretty normal:"Typical/Maximum power dissipation 0.33 Watt / 0.74 Watt"(http://www.cpu-world.com/CPUs/8035/Intel-P8035L.html)Those are old parts, they take a lot of current.

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 04, 2017, 05:04:46 pm
content: Good evening; thank you for the information. How to check the correct operation of the P8035L microprocessor with its memory P8355 ?? Thanks

author: janoc
author_rank: Super Contributor
timestamp: March 05, 2017, 04:22:33 pm
content: Datasheet, then check with the scope/logic analyzer whether the various bus control signals are there. That's how I would start checking that. It is the old 8048 Intel MCU family which is well known, so the documentation shouldn't be hard to find.That MCU has no internal memory by itself, so if it is not attempting to access the external one, it is likely dead. But check also whether it is getting reset properly, whether there is clock, etc. The usual stuff.

author: lionelkjh
author_rank: Frequent Contributor
timestamp: March 06, 2017, 09:10:57 am
content: Hello; thanks, I have verified, and I believe that the microprocessor is dead. The origin is: P8035L INTEL77, and I found on the internet: P8035AHL. Are they identical (besides manufacturing by intel)?

author: james_s
author_rank: Super Contributor
timestamp: March 06, 2017, 04:34:43 pm
content: Doesn't it say in the datasheet?Unless it costs a lot, I would probably buy one and try it. Here's a P8035Lhttp://www.ebay.com/itm/HN462716G-MC14411P-P8035L-AM9555DC-/272567104020?You get some other bonus parts included for free too.

author: janoc
author_rank: Super Contributor
timestamp: March 07, 2017, 01:34:27 pm
content: Quote from: james_s on March 06, 2017, 04:34:43 pmWell, but those are obviously pulls from some old board. Who knows what is their state and whether they even work. That board could have been fried by a lightning strike for all you know or the guy took a heat gun to it to desolder the parts, frying them.Better try to find some NOS or perhaps a clone - these chips were made by several manufacturers, not only by Intel.E.g. this Dutch company is offering one:http://www.budgetronics.eu/index.php?action=article&aid=12071&lang=ENI believe the -AHL version is a faster/improved version of the original but better verify whether they are pin compatible. Most likely they are. The AHL version goes up to 11MHz, the original one only to 6MHz.This page shows possible clones and compatible replacements from other manufacturers:Intel P8035L(scroll to bottom right corner, there is a box with "Find 8035 CPUs with:", select "Any frequency", check "Same socket" and it will give you a list)

author: james_s
author_rank: Super Contributor
timestamp: March 07, 2017, 04:46:52 pm
content: I've had good luck with pulls from some old board. Yeah it's a gamble, but when it's a few dollars, who cares? Pop it in, if it still doesn't work then either find a NOS part or investigate elsewhere.

author: janoc
author_rank: Super Contributor
timestamp: March 07, 2017, 11:20:30 pm
content: Quote from: james_s on March 07, 2017, 04:46:52 pmThat makes sense when you have the board in your junkbox. But if you have to order it on eBay and a new part is only little more expensive, why to add another possible failure point to your troubleshooting?If the part is bad, you will still have to order the good one - wasting time and money.

author: james_s
author_rank: Super Contributor
timestamp: March 07, 2017, 11:50:00 pm
content: Well yeah if you can find a new part. In my case the part I needed recently was long out of production. I found a used one that turned out to be fine, but in the end that wasn't the problem in the first place.