W79E825A/824A/823B/822B Data Sheet
26 ICP(IN-CIRCUIT PROGRAM) FLASH PROGRAM
The contexts of flash in W79E825 series are empty by default. User must program the flash EPROM
by external Writer device or by ICP (In-Circuit Program) tool.
In the ICP tool, the user must take note of ICP’s program pins used in system board. In some
application circuits, the pins are located at P1.5, P0.4 and P0.5, as below figure. During ICP
programming, P1.5 must be set to high voltage (~10.5V), and keeping this voltage to update code,
data and/or configure CONFIG bits. After programming completion, the high voltage of P1.5 should be
released. So, it is highly recommended user power off then power on after ICP programming has
completed on the system board.
Upon entry into ICP program mode, all pin will be set to quasi-bidirectional mode, and output to level
“1”.
The W79E825 series support programming of Flash EPROM (16K/8K/4K/2K bytes AP Flash EPROM)
and NVM data memory (256/128 bytes). User has the option to program the AP flash and NVM either
individually or both.
Vcc
ICP Power
Jumper
ICP Connector
Vdd
Jumper
Vdd
Vpp
RST
P0.4
P0.5
To Reset or Input Pin
To I/O pin
Data
Clock
Vss
To I/O pin
Vss
W79E825 Series
System Board
Figure 26-1: Application Circuit of ICP
Note: 1. When using ICP to upgrade code, the P1.5, P0.4 and P0.5 must be taken within design system board.
2. After program finished by ICP, to suggest system power must power off and remove ICP connector then power
on.
3. It is recommended that user performs erase function and programming configure bits continuously
without any interruption.
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