HCS515 datasheet(12/32 Pages) MICROCHIP

12 / 32 page

HCS515

DS40183D-page 12

4.2.7

ERASE ALL

The erase all command (Figure 4-6) erases all the

transmitters in the decoder. After the command and two

dummy bytes are clocked in, the clock line must be

asserted to activate the command. After a successful

completion of an erase all command, the data line is

asserted until the clock line goes low.

FIGURE 4-6:

ERASE ALL

4.2.8

ACTIVATE LEARN

The activate learn command (Figure 4-7) is used to

activate a transmitter learning sequence on the

decoder. The command consists of a Command mode

activation sequence, a command byte, and two dummy

bytes. The decoder will respond by taking the data line

high to acknowledge that the command was valid and

that learn is active.

Upon reception of the first transmission, the decoder

will respond with a learn status message (Figure 4-8).

During learn, the decoder will acknowledge the recep-

tion of the first transmission by taking the data line high

for 60 ms. The controlling microcontroller can clock out

at most 8 bits, which will all be zeros. All of the bits of

the status byte are zero, and this is used to distinguish

between a learn time-out status string and the first

transmission received string. The controlling microcon-

troller must ensure that the clock line does not go high

60 ms after the falling edge of the data line, for this will

terminate learn.

Upon reception of the second transmission, the

decoder will respond with a learn status message

(Figure 4-9).

The learn status message after the second transmis-

sion consists of the following:

• 1 START bit.

• The function code [S3:S0] of the message is

zero, indicating that this is a status string.

• The RESULT bit indicates the result of the learn

sequence. The RESULT bit is set if successful

and cleared otherwise.

• The OVR bit will indicate whether an exiting trans-

mitter is over written. The OVR bit will be set if an

existing transmitter is learned over.

•The [CNT3…CNT0] bits will indicate the number of

transmitters learned on the decoder.

•The [TX3…TX0] bits indicate the block number

used during the learning of the transmitter.

FIGURE 4-7:

LEARN MODE ACTIVATION

Decoder DATA

MSB

Command Byte

START Command

LSB

TERA

Subcommand Byte

Dummy Byte

CLK

µC DATA

Acknowledge

MSB

LSB

MSB

LSB

TACK

TRESP

TACK2

ecoder DATA

MSB

Command Byte

START Command

LSB

TLRN

Dummy Byte

CLK

µC DATA

Acknowledge

MSB

LSB

MSB

LSB

TACK

TRESP

TACK2

HCS515 数据表(PDF) 12 Page - Microchip Technology

HCS515 数据表(HTML) 12 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

数据表下载