Datasheet

L6474 Programming manual

Doc ID 022529 Rev 3 45/52

9.2.3 SetParam (PARAM, VALUE)

The SetParam command sets the PARAM register value equal to VALUE; PARAM is the

respective register address listed in Ta bl e 16 .

The command should be followed by the new register VALUE (most significant byte first).

The number of bytes composing the VALUE argument depends on the length of the target

Some registers cannot be written (see Ta bl e 16); any attempt to write one of those registers

causes the command to be ignored and the WRONG_CMD flag to rise at the end of

command byte, the same is true when an unknown command code is sent (see

Section 9.1.13).

Some registers can only be written in particular conditions (see Ta bl e 1 6); any attempt to

write one of those registers when the conditions are not satisfied causes the command to be

ignored and the NOTPERF_CMD flag to rise at the end of last argument byte (see

Section 9.1.13).

Any attempt to set an inexistent register (wrong address value) causes the command to be

ignored and the WRONG_CMD flag to rise at the end of command byte, the same is true

when an unknown command code is sent.

9.2.4 GetParam (PARAM)

This command reads the current PARAM register value; PARAM is the respective register

address listed in Ta bl e 16.

The command response is the current value of the register (most significant byte first). The

number of bytes composing the command response depends on the length of the target

The returned value is the register one at the moment of GetParam command decoding. If

All registers can be read anytime.

Table 32. SetParam command structure

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

0 0 0 PARAM From host

VALUE Byte 2 (if needed)

VALUE Byte 1 (if needed)

VALUE Byte 0

Table 33. GetParam command structure

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

0 0 1 PARAM from host

ANS Byte 2 (if needed) to host

ANS Byte 1 (if needed) to host

ANS Byte 0 to host