Owner manual

AT90C8534

Signal Names

In this section, some pins of the AT90C8534 are referenced by signal names describing their function during parallel pro-

gramming. See Figure 35 and Table 11. Pins not described in Table 11 are referenced by pin names.

The XA1/XA0 pins determines the action executed when the XTAL1 pin is given a positive pulse. The coding is shown in

Table 12.

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 13.

Figure 35. Parallel Programming

Table 11. Pin Name Mapping

Signal Name in

Programming Mode Pin Name I/O Function

RDY/BSY

INT1 O “0”: Device is busy programming, “1”: Device is ready for new command

OE ADIN1 I Output Enable (active low)

ADIN2 I Write Pulse (active low)

BS ADIN3 I Byte Select (“0” selects low byte, “1” selects high byte)

XA0 ADIN4 I XTAL1 Action Bit 0

XA1 ADIN5 I XTAL1 Action Bit 1

DATA INT0, PA6-0 I/O Bi-directional Data Bus (output when OE

is low)

AT90VC8534

VCC

+5V

RESET

GND

XTAL1

RESET

RDY/BSY

XA0

XA1

DATA

PEN

INT1

ADIN1

ADIN2

ADIN3

ADIN4

ADIN5

INT0,PA6-0