Enter programming mode, And table 37, Table 37 ar – Rainbow Electronics AT90LS8535 User Manual

Page 94: Table 38, Table 39

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94

AT90S/LS8535

1041H–11/01

Enter Programming Mode

The following algorithm puts the device in Parallel Programming Mode:

1.

Apply supply voltage according to Table 36, between V

CC

and GND.

2.

Set the RESET and BS pin to “0” and wait at least 100 ns.

3.

Apply 11.5 - 12.5V to RESET. Any activity on BS within 100 ns after +12V has
been applied to RESET, will cause the device to fail entering programming mode.

Table 37. 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)

BS

PD4

I

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

XA0

PD5

I

XTAL Action Bit 0

XA1

PD6

I

XTAL Action Bit 1

DATA

PB7 - 0

I/O

Bi-directional Data Bus (Output when OE is low)

Table 38. XA1 and XA0 Coding

XA1

XA0

Action when XTAL1 is Pulsed

0

0

Load Flash or EEPROM Address (high or low address byte determined by BS)

0

1

Load Data (High or low data byte for Flash determined by BS)

1

0

Load Command

1

1

No Action, Idle

Table 39. Command Byte Bit Coding

Command Byte

Command Executed

1000 0000

Chip Erase

0100 0000

Write Fuse Bits

0010 0000

Write Lock Bits

0001 0000

Write Flash

0001 0001

Write EEPROM

0000 1000

Read Signature Bytes

0000 0100

Read Lock and Fuse Bits

0000 0010

Read Flash

0000 0011

Read EEPROM

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