SC9821C

HANGZHOU SILAN MICROELECTRONICS CO.,LTD

REV:1.0

2006.07.21

Http: www.silan.com.cn

Page 7 of 18

Address[3:0]:

Assign the operation object. Note: When Address [3:0] = 4’

b1111, all the Guests will

be operation objects (common), but at this time, the Guest should close the feedback

channel and only receive the data sending by Host. And when select the only Guest, it

can be bidirectional communication (respective).

BurstLength:

Denote the operation length of Burst.

Addr:

8-bit addressing address of Host.

Ack:

It is an acknowledge signal. In the address check all modes; this signal is only used as

leading data (low level) to denote the beginning of the data pack because the

feedback channel of Guest is closed. In one-to-one mode, After the Guest receives a

serial of pack leading with Command byte; it must feed back to Host an Ack signal in

defined time which is decided by Host itself. When sending the data, if the

transmission direction is from Host to Guest this time, Guest must feed back an Ack

signal in defined time every time it receives a data; if overstep, Host will pull up

DataAvail and end this transmission. When Host sends the data, if there is other data

needed transmission after Host receives the Ack signal, it must transmit following the

next cycle; When Host receives data, it must come into receiving state (otherwise end

this transmission directly) after Host receives the Ack signal.

Data:

The transmitted data is following the leading Ack signal, and the latter limited a data

when Burst is 0. When over the provision data, the receiver may not correspond to Ack

signal.

According to above description, if complete the operations from Host to Guest, the read-write operation is as

followed:

Adopt 8-bit effective address, and assume the addressing address of guest is 0H:

Figure 2 SSI write operation

Figure 3 SSI read operation