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DLP-245PB-G

USB / Microcontroller Module (Lead-Free)

Unspecified 

TOKEN I/O

The 16F877A microcontroller on the DLP-245PB-G is shipped from the factory preprogrammed

with firmware that provides rudimentary access to the port pins via either the VCP or DLL drivers.

Features include the ability to read and write individual port pins as well as 8-bit port reads and

writes.

The firmware in the DLP-245PB-G also provides access to the 16F877A’s A/D converter,

EEPROM memory, and communications with digital temperature-sensing devices.

Commands sent to the Token I/O firmware must adhere to a specific communications protocol.

Each command sequence contains the following information:

Byte 0:

Byte 1:

Byte 2…n-1:

Byte n:

Number of bytes in command sequence

Command

Parameter/Data bytes

Checksum

The checksum is computed by exclusive-OR-ing every byte in the string. If the same checksum

is calculated by the 16F877A upon receipt of the packet, then a single-byte reply of 0x55 is

returned to the host. In the event of a checksum error, the 16F877A will return an error code of

0xAA. For example, setting port PIN_A1 high would require the following string of bytes:

0x03, 0xA6, 0x29, 0x01, 0x8D

Definition of the Bytes:

0x03 – Number of bytes in command (checksum excluded)

0xA6 – Command for set port pin high/low

0x29 – Affected port pin

0x01 – Desired state of port pin

0x8D – Checksum of previous 4 bytes

The port pins equate to hexadecimal numeric constants as defined here:

PORT A:

PIN_A0 0x28, PIN_A1 0x29, PIN_A2 0x2A,

PIN_A3 0x2B, PIN_A4 0x2C, PIN_A5 0x2D

V2.3

Page 6 of 15

February 2007

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