Intel 8XC196NT User Manual page 538

PPW (or SP_PPW)
The PPW register is loaded from the external EPROM (locations 14H and 15H) in auto programming
mode. The SP_PPW register is loaded from the internal test ROM in serial port programming mode.
The default pulse width for serial port programming is longer than required, so you should change the
value before beginning to program the device. (See "Changing Serial Port Programming Defaults" on
page 15-33.) The PPW_VALUE determines the programming pulse width, which must be at least
100 µs for successful programming.
15
1 PPW14
7
PPW7 PPW6
Bit Bit
Number Mnemonic
15 1
14:0 PPW14:0
PPW13 PPW12
PPW5 PPW4
Set this bit for proper device operation.
PPW_VALUE.
This value establishes the programming pulse width for auto programming
or serial port programming. For a 100-µs pulse width, use the following
formula and round the result to the next higher integer. For auto
programming, write this value to the external EPROM (see "Auto
Programming Procedure" on page 15-29). For serial port programming,
write this value to the internal memory (see "Changing Serial Port
Programming Defaults" on page 15-33).
(
PPW_VALUE = 0.6944 F
PPW11 PPW10
PPW3 PPW2
Function
× )
– 1
os c
REGISTERS
PPW (or SP_PPW)
no direct access
8
PPW9 PPW8
0
PPW1 PPW0
C-43