Read Flash Memory ATMEL AT89C52 Microcontroller - Page 1
Forum section: electronics / general

author: 2X
author_rank: Frequent Contributor
timestamp: April 06, 2025, 03:23:09 pm
content: Hi,I am trying to read the flash memory from the ATMEL AT89C52 microcontroller (from a damaged PCB) with the T56 universal programmer, but I am getting an error (images 2,3,4). The error says that the pins 38 & 39 from the microcontroller don't contact with the zif connector from the programmer. I measured all the pins from the microcontroller with the multimeter in diode mode and all pins show approximately 0.6V except from the pins 38 & 39 where show OL (image 9 - I suspect that these pins are damaged). Also, I remove the Check ID (images 4 &5) option from the programmer’s software and the programmer shows "Read Succeed" but didn't read something at all… all are FF.There is something where I could do to read the flash memory?

author: PCB.Wiz
author_rank: Super Contributor
timestamp: April 07, 2025, 04:07:33 am
content: If the part is secured, you will not be able to easily read the contents.If pins are damaged, the chip may also be internally damaged.

author: bobxyz
author_rank: Contributor
timestamp: April 07, 2025, 04:37:29 am
content: Your first screenshot says: "No Programmer Found" and "Demo running as TL866II Plus Programmer". In other words, it's running in demo mode and is ignoring the actual programmer.

author: 2X
author_rank: Frequent Contributor
timestamp: April 07, 2025, 07:46:27 pm
content: Quote from: bobxyz on April 07, 2025, 04:37:29 amIn first picture I haven't connect the programmer. The programmer is connected fine but I can't read the MCU.

author: 2X
author_rank: Frequent Contributor
timestamp: April 07, 2025, 07:53:52 pm
content: Quote from: PCB.Wiz on April 07, 2025, 04:07:33 amThe MCU working... it is from a control panel of a Fendt 250V 1991 tractor. The problem is that not only digits on the LCD display are displayed (I have install new LCDs and LCDs drivers).

author: Atlan
author_rank: Frequent Contributor
timestamp: April 09, 2025, 05:13:33 pm
content: It is very likely that read protection is enabled.

author: wraper
author_rank: Unknown
timestamp: April 09, 2025, 05:45:29 pm
content: This MCU has parallel programming interface. Most of the pins are required for programming. So if you have some I/O damaged, you won't get the data out even if read protection is not enabled.https://www.microchip.com/content/dam/mchp/documents/OTH/ApplicationNotes/ApplicationNotes/DOC0285.PDFEdit, you could try baking the chip to ~150oC. There is some chance that if it's a bond wire issue, they may regain contact for a while.

author: 2X
author_rank: Frequent Contributor
timestamp: April 14, 2025, 06:26:04 pm
content: I bought some new chips and all are read it fine.

author: 2X
author_rank: Frequent Contributor
timestamp: April 14, 2025, 06:29:17 pm
content: Quote from: wraper on April 09, 2025, 05:45:29 pmThere is a way for serial programming?

author: up8051
author_rank: Frequent Contributor
timestamp: April 14, 2025, 06:48:19 pm
content: No.AT89C52 has only parallel programming mode.

author: mikerj
author_rank: Super Contributor
timestamp: April 14, 2025, 08:03:56 pm
content: Are you sure this missing segments aren't caused by a PCB fault, e.g. broken trace or via?

author: 2X
author_rank: Frequent Contributor
timestamp: April 14, 2025, 08:14:06 pm
content: Quote from: mikerj on April 14, 2025, 08:03:56 pmYes. I checked all of them.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: April 14, 2025, 10:13:43 pm
content: Quote from: 2X on April 07, 2025, 07:53:52 pmYour only option may be to ask the supplier for a programmed part, or a replacement board ?How functional is the unit? Aside from visual effects, how partially operational is it ?