Programming Atmel AT89C51ED2 using ISP

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sensor_one
Posts: 2
Joined: 06 Dec 2020 00:48

Programming Atmel AT89C51ED2 using ISP

Postby sensor_one » 06 Dec 2020 01:47

We are attempting to program the Atmel device AT89C51ED2 using the ISP method.

The programmer is Dataman 48Pro2C.
The device selected is Atmel AT89C51ED2-xm (ISP).

My questions are:

1. It's not clear to me what the Hardware Security Byte (HSB) check boxes indicate in the attached screen shot. When checked are they SET (1) (unprogrammed) or CLEARED (0) (programmed) for the X2 and Boot Loader Jump Bit (BLJB) check boxes?

2. Why are the HSB XRAM and "User Memory Lock Bits" grayed out as shown in same screen shot? This is not the case in parallel/ZIF mode where they are not grayed out.

3. Why are the following MCU pins used in the ISP connector, see (2) screen shots attached, they seem redundant?
PSEN, EA/VPP and ALE/PROG

Our ISP adapter board does not have these pins connected. Our circuit board has MCU pins
PSEN, EA/VPP and ALE/PROG pulled HIGH. The ISP process seems to work and gives a success
message but our user app program never runs afterwards. The Atmel datasheet (could not attach)
does not mention that these MCU pins are needed in ISP.

4. Why does your forum not allow a PDF to be attached?

Michael
Attachments
Dataman isp pinout for AT89C51ED2.png
Dataman isp circuit for AT89C51ED2.png
Dataman device options for AT89C51ED2 using ISP.png

Dataman (Neil Parker)
Posts: 828
Joined: 10 Nov 2011 09:51

Re: Programming Atmel AT89C51ED2 using ISP

Postby Dataman (Neil Parker) » 08 Dec 2020 15:00

Hello sensor_one,

>> 1. It's not clear to me what the Hardware Security Byte (HSB) check boxes indicate in the attached screen shot.
>> When checked are they SET (1) (unprogrammed) or CLEARED (0) (programmed) for the X2 and Boot Loader Jump Bit (BLJB) check boxes?

They are CLEARED (0) (programmed) when checked. And they are SET (1) (unprogrammed) when unchecked.


>> 2. Why are the HSB XRAM and "User Memory Lock Bits" grayed out as shown in same screen shot?
>> This is not the case in parallel/ZIF mode where they are not grayed out.

Because they can only be read in ISP (UART) mode.

Quoted from Device info section of our software:
"
'Software security byte' is programmed by way of 'Security level'. If operating in ISP mode, it's not possible to unprogrammed already programmed HSB bits. These bits can be unprogrammed only while operating in ZIF mode (parallel mode).
"


>> 3. Why are the following MCU pins used in the ISP connector, see (2) screen shots attached, they seem redundant?
>> PSEN, EA/VPP and ALE/PROG

It is necessary to set them in accordance with the serial programming specifications as follows:
PSEN = 0, EA = 1, ALE = 1 or not connected.


>> Our ISP adapter board does not have these pins connected. Our circuit board has MCU pins
>> PSEN, EA/VPP and ALE/PROG pulled HIGH. The ISP process seems to work and gives a success
>> message but our user app program never runs afterwards. The Atmel datasheet (could not attach)
>> does not mention that these MCU pins are needed in ISP.

Please see the related part of the datasheet for the explanation:

ISP.PNG

I hope this answers your questions.

Best regards,


Neil Parker
Dataman Programmer

sensor_one
Posts: 2
Joined: 06 Dec 2020 00:48

Re: Programming Atmel AT89C51ED2 using ISP

Postby sensor_one » 08 Dec 2020 18:33

Thanks Neil for the answers, it was helpful.

However, you did not answer question 4 above.

Michael

Dataman (Neil Parker)
Posts: 828
Joined: 10 Nov 2011 09:51

Re: Programming Atmel AT89C51ED2 using ISP

Postby Dataman (Neil Parker) » 09 Dec 2020 09:20

Hello Michael,

Apologies. I did ask our web team and *.pdf doesn't seem to be a supported file format on this forum platform.

Best regards,


Neil Parker
Dataman programmers


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