4.1.3 Time-outs

The Programming Executive uses no Watchdog Timer or time-out for transmitting responses to the programmer. If the programmer does not follow the flow control mechanism using PGECx, as described in Communication Interface and Protocol, it is possible that the Programming Executive will behave unexpectedly while trying to send a response to the programmer. Since the PE has no time-out, it is imperative that the programmer correctly follows the described communication protocol.

As a safety measure, the programmer should use the command time-outs identified in Table 4-1. If the command time-out expires, the programmer should reset the PE and start programming the device again.

Table 4-1. Programming Executive Command Set
OpcodeMnemonicLength (16-bit words)Time-outDescription

0x0

SCHECK

1

1 ms

Sanity check

0x1

Reserved

N/A

N/A

—

0x2

READP

4

1 ms/row

Read ‘N’ 24-bit instruction words of the user Flash memory, Configuration Word, or Device ID register, starting from the specified address.

0x3

PROG2W

6

5 ms

Program a double instruction word of code memory at the specified address and verify it.

0x4

Reserved

N/A

N/A

This command is reserved; it will return a NACK.

0x5

PROGP

195

5 ms

Program 128 words of program memory at the specified starting address, then verify.

0x6

Reserved

N/A

N/A

This command is reserved; it will return a NACK.

0x7

ERASEB

1

125 ms

Bulk Erase user memory.

0x8

Reserved

N/A

N/A

This command is reserved; it will return a NACK.

0x9

ERASEP

3

25 ms

Command to erase a page.

0xA

Reserved

N/A

N/A

This command is reserved; it will return a NACK.

0xB

QVER

1

1 ms

Query the Programming Executive software version.

0xC

CRCP

5

1s

Perform a CRC-16 on the specified range of memory.

0xD

Reserved

N/A

N/A

This command is reserved; it will return a NACK.

0xE

QBLANK

5

700 ms

Query to check whether the code memory is blank.