WAN0143 Datasheet, PDF (4/6 Pages) Wolfson Microelectronics plc – ADA and MASK Timing on WM9712

WAN_0143
ALTERNATIVE MASK FUNCTION
When MASK = 11, synchronous mode, conversions are commanded on the rising and falling edges
of MASK input signal. However, there is an alternative operation which allows a pulse to be applied
to the MASK pin resulting in only one conversion taking place. In this setup the edges of the pulse
are too close together to allow two separate conversions to be commanded. Figure 3 details this
operation and the timing associated.
t _PULSE
MASK
Frames
(SYNC)
AUXADC Conversion
(MASK = 11)
t _DEL
t _DEL
Conv
t _DEL
Conv
Figure 3 MASK PULSE delay timings (tDEL = 2 frames)
PARAMETER
MASK Pulse Width
Frame Delay set by register 76h
SYMBOL
tPULSE
tDEL
MIN
100ns
0
TYP
MAX
< tDEL
288
UNIT
ns
frames
ADA TIMING
Whenever data becomes available from the touchpanel ADC, the internal ADA signal goes high and
remains high until the data has been read from register 7Ah (if SLEN = 0) or until it has been sent out
on an AC-Link slot (if SLEN = 1).
If ADA is configured to be output on pin 47 the timing associated with this signal will be as follows.
BCLK
SYNC
ADA
t _ADA
t _ADA
Figure 4 ADA Timings
PARAMETER
Delay from SYNC to ADA
SYMBOL
tADA
MIN
TYP
200ns
MAX
UNIT
ns
w
Rev 1.0 March 2004
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