Datasheet

DS_INLC10AQ Revision 1.0_B

Inova Semiconductors Confidential

Page 21 of 35

4.1.8 Timeouts

The digLED_Init_Strip, all the digLED_Read, and the digLED_Ping commands initiate upstream data

transmission. With the digLED_Init_Strip and the read commands all nodes are expected to send a

response to the host. The digLED_Ping requires only the last node in the LED chain to respond. However,

in all cases each node needs to await all responses originating from the nodes downstream. Thereafter

either the node’s own response is transmitted or new commands are accepted. Only the last node in the

LED chain may immediately transmit its response.

In case there is an error with the chain downstream, not all expected responses may arrive. Thus, each of

the commands expecting a response waits for a certain time only and then returns to its previous state

without having transmitted the node’s response data.

The lengths of the timeouts depend on the respective command. They are calculated to account for the

worst-case oscillator frequency tolerance. I.e. the waiting node has a high-speed clock and all the nodes

waited for have a low speed clock. The hardware implementation uses an internally divided clock for the

timeout counter:

f[timeout] = f[osc] / 214

With the nominal clock frequency of 16MHz the counter’s resolution results to 1.024ms.

Command

Max. counter value

Min. timeout

Nom. timeout

Max. timeout

Units

digLED_Init_Strip

992

780.6

1015.3

1451.2

ms

digLED_Read_xxx

427

335.6

436.7

624.6

ms

digLED_Ping

62

48.0

63.0

90.7

ms

Table 19 - Timeouts