- While
txrequesths
is Low, the lane module ignores the value oftxdatahs[7:0]
. To begin transmission, the protocol drives thetxdatahs
signal with the first byte of data and asserts thetxrequesths
signal. - This data byte is accepted by the D-PHY on the first rising edge of
txbyteclkhs
withtxreadyhs
also asserted. Now, the protocol logic drives the next data byte ontotxdatahs
. After every rising clock cycle withtxreadyhs
active, the protocol supplies a new valid data byte or ends the transmission. - After the last data byte has been transferred to the lane module,
txrequesths
is driven Low to cause the lane module to stop the transmission and enter Stop state. - The
txreadyhs
signal is driven Low aftertxrequesths
goes Low.
This section describes a high-speed transmission by the D-PHY TX (Master) IP.
The minimum number of bytes transmitted can be as small as one.
Note: The
txrequesths
signal of the TX clock lane must be asserted to start the
high-speed data transfer. The following figure shows the high-speed transmission by the D-PHY TX (Master) IP.
Figure 1. High-Speed Mode Data Transfer from D-PHY TX (Master)
The start-up time can be calculated using.
2*LPX_TIME + HS_PREPARE_TIME + HS_ZERO_TIME +
CDC_DELAY.
Where HS_PREPARE
and HS_ZERO
are D-PHY protocol timing parameters and maximum values used in the IP.
You cannot control the HS_PREPARE
and HS_ZERO
values as they are automatically calculated based on the line rate. You
can configure LPX using the AMD Vivado™
IP Catalog. CDC_DELAY
will be 30 ns + 2 txbyteclkhs.