Datasheet

210
ATmega8A [DATASHEET]
8159E–AVR–02/2013
25.5 Page Size
25.6 Parallel Programming Parameters, Pin Mapping, and Commands
This section describes how to parallel program and verify Flash Program memory, EEPROM Data memory, Mem-
ory Lock Bits, and Fuse Bits in the ATmega8A. Pulses are assumed to be at least 250 ns unless otherwise noted.
25.6.1 Signal Names
In this section, some pins of the ATmega8A are referenced by signal names describing their functionality during
parallel programming, see Figure 25-1 and Table 25-7. Pins not described in the following table are referenced by
pin names.
The XA1/XA0 pins determine the action executed when the XTAL1 pin is given a positive pulse. The bit coding is
shown in Table 25-9.
When pulsing WR
or OE, the command loaded determines the action executed. The different Commands are
shown in Table 25-10.
Figure 25-1. Parallel Programming
Table 25-5. No. of Words in a Page and no. of Pages in the Flash
Flash Size Page Size PCWORD No. of Pages PCPAGE PCMSB
4K words (8K bytes) 32 words PC[4:0] 128 PC[11:5] 11
Table 25-6. No. of Words in a Page and no. of Pages in the EEPROM
EEPROM Size Page Size PCWORD No. of Pages PCPAGE EEAMSB
512 bytes 4 bytes EEA[1:0] 128 EEA[8:2] 8
VCC
+5V
GND
XTAL1
PD1
PD2
PD3
PD4
PD5
PD6
PC[1:0]:PB[5:0]
DATA
RESET
PD7
+12 V
BS1
XA0
XA1
OE
RDY/BSY
PAGEL
PC2
WR
BS2
AVCC
+5V