Flash Magic Forum

In-System Programming Support => P89V51Rx2/P89LV51Rx2 => Topic started by: Barry Grieves on January 31, 2005, 06:51:03 PM

Title: P89V51RD2 issues
Post by: Barry Grieves on January 31, 2005, 06:51:03 PM
The problem I had programming the V part was fixed by using a reset chip (Microchip MCP810T) instead of relying on a capacitor to VDD on the reset line.
The part still did not work properly, this was due to the micro not seeing an input pin (P3.3) going low. With the C part, the pin was going down to 0.1V, with the V part it did not go below 2V (datasheet states 0.2VDD-.1V, ie 0.9V required). I would attribute this to the pullups on the V part being stronger than on the C part.