4.5 I/O Transmission from the ECC204-TFLXAUTH
When the ECC204-TFLXAUTH is awake and not busy, the host can retrieve the current output buffer contents from the device using an I/O read. If valid command results are available, the size of the group returned is determined by the particular run command. Otherwise, the size of the group (and the first byte returned) will always be four: count, status/error and 2-byte CRC.
| Name | I/O Name | Direction | Description |
|---|---|---|---|
| Device Address | Device Address | To client | This byte selects a particular device on the I/O interface and the ECC204-TFLXAUTH will be selected if bits 1 through 7 of this byte match bits 1 through 7 of the Device_Address byte in the Configuration zone. Bit 0 of this byte is the R/W bit and must be one to indicate that the bytes following the device address travel from the client to the host (read). |
| Data | Data 1, N | To host | The output group, consisting of the count, status/error byte or the output packet followed by the 2-byte CRC. |
The status, error or command outputs can be read repeatedly by the host.
Each time a Read command is sent to the ECC204-TFLXAUTH along the I/O interface, the device transmits the next sequential byte
in the output buffer. See the following section for details on how the device handles
the address counter.
If the ECC204-TFLXAUTH is busy or asleep, it will
NACK the device address on a read sequence. If a partial command is sent to the device
and a read sequence [Start + DeviceAddress(R/W ==
R)] is sent to the device, the ECC204-TFLXAUTH will
NACK the device address to indicate that no data are available to be read.