Timer started
Timer loaded
DSI_TIMING1[31] TA_TO = 0x0
by software
DSI_TIMING1[31] TA_TO = 0x1
RESET
DSI_TIMING1[31] TA_TO = 0x0 by software
PPI TurnRequest signal
asserted by DSI protocol
engine
Time-out
IDLE
DSI_TIMING1[31] TA_TO = 0x0 by hardware
BTA accepted by peripheral
TA_TO
interrupt
generation and
ForceTxStopMode
sequence
dss-173
Public Version
www.ti.com
Display Subsystem Functional Description
Figure 7-97. TurnRequest FSM
The DSI protocol engine asserts TurnRequest signal during one TxClkEsc cycle when the turn-around is
enabled through the DSS.
[6] BTA_EN bit (for more information, see
, Bus
Turnaround). The DSS.
[31] TA_TO bit is set/reset by software to respectively enable/disable
the timer for turnaround procedure failure. It can be reset by software or automatically by hardware when
the time out occurs.
The timer is loaded with the value in number of DSI_FCLK cycles:
[28:16] TA_TO_COUNTER x ((
[30] TA_TO_X16 x 15) + 1) x
((
[29] TA_TO_X8 x 7) + 1).
When the TA_TO_IRQ interrupt is generated (turn-around timer expired, and procedure failed), the
hardware automatically asserts ForceTXStopMode in order for the DSI_PHY to drive LP-11 stop state.
The ForceTXStopMode timer is used to define the minimum duration of LP-11 state. The Stop State can
be longer if there is no activity.
The hardware resets the ForceTXStopMode bit, followed by an internal logic reset except all register
values and TX FIFO content, then resets the DSS.
[0] IF_EN bit. The software should take
action to recover by resetting the peripheral, for example, if it is not responding. It should wait for
DSS.
[15] FORCE_TX_STOP_MODE_IO and DSS.
[0] IF_EN bits to be reset to 0
before starting the recovery sequence.
7.4.3.7.4 Peripheral Reset Timer
The peripheral reset timer is not implemented in the DSI protocol engine module. Such as the Twakeup
timer, a general-purpose timer (GPTimer)should be used in case of reset of the peripheral to determine
when the peripheral is ready again for operation.
7.4.3.7.5 HS TX Timer
The HS TX timer is used to detect when the host has been in TX mode for too long. When time-out
occurs, the EOT is forced. The timer is reloaded when a start of high speed transmission occurs. It is
enabled/disabled by software through the DSS.
[31] HS_TX_TO bit. The interrupt
HS_TX_TO_IRQ is generated when the timer expires. The DSS.
[14] HS_TX_TO_IRQ
bit is set to 1 when the HS TX time-out occurs.
1677
SWPU177N – December 2009 – Revised November 2010
Display Subsystem
Copyright © 2009–2010, Texas Instruments Incorporated