Rainbow Electronics ATmega161L - Manual (Page 118)

118
ATmega161(L)
1228C–AVR–08/02
Parallel Programming This section describes how to parallel program and verify Flash Program memory,
EEPROM Data memory, Lock bits and Fuse bits in the ATmega161. Pulses are
assumed to be at least 500 ns unless otherwise noted.
Signal Names In this section, some pins of the ATmega161 are referenced by signal names describing
their functionality during parallel programming (see Figure 75 and Table 42). Pins not
described in the following table are referenced by pin name.
The XA1/XA0 pins determine the action executed when the XTAL1 pin is given a posi-
tive pulse. The bit codings are shown in Table 43.
When pulsing WR or OE, the command loaded determines the action executed. The
command is a byte where the different bits are assigned functions as shown in Table 44.
Figure 75. Parallel Programming
Table 42. Pin Name Mapping
Signal Name in
Programming Mode Pin Name I/O Function
RDY/BSY PD1 O 0: Device is busy programming; 1: Device is ready
for new command
OE PD2 I Output Enable (Active low)
WR PD3 I Write Pulse (Active low)
BS1 PD4 I Byte Select 1 (“0” selects Low byte, “1” selects
High byte)
XA0 PD5 I XTAL Action Bit 0
XA1 PD6 I XTAL Action Bit 1
ATmega161
VCC
+5V
GND
XTAL1
PD1
PD2
PD3
PD4
PD5
PD6
PB7 - PB0 DATA
RESET
PD7
+12 V
BS1
XA0
XA1
OE
RDY/BSY
PAGEL
PA0
WR