Touchscreen Mode 11—Auto - Freescale Semiconductor MCF52277 Reference Manual

Touchscreen Controller/Analog-to-Digital Converter
Figure 22-18 illustrates a typical operation sequence when TSE = 1, CALA = 0, MODE = 11, and
AUTO = 0. The following example assumes MIDLECNT ≠ 0, RIDLECNT ≠ 0, AZE = 1.
BIACTRL
Pen
SELREFP
SELREFN
det ect i on
SELINP
a
PENDOWN_IRQ
ASPE
PENUP_IRQ
a) When ASP configuration is complete, the ASP parks on the pen detection state.
b) Pen-down event is detected and the pen-down interrupt occurs.
c) MCU responds to the interrupt and masks the pen-down interrupt. It is recommended to clear
the FIFO in this step.
d) MCU sets ASPE to initiate the measurement operation.
e) ASP begins one round of X/Y coordinate and active auxiliary channels measurements.
f) ASP completes one round of measurement and enters the pen-detect state again. If the FIFO
watermark level is set properly, the FIFO watermark interrupt may be used to upload the
conversion results here.
g) Pen-up event is detected and the pen-up interrupt occurs. If FIFO watermark interrupt is not
used, the conversion results may be uploaded here.
h) ASPE is cleared automatically or by software depending on the setting of PENE. The ASP is
ready to detect the next pen-down event.
i) MCU clears the pen-up interrupt.
If MIDLECNT is cleared, only need to remove IDLE measurement phase.
22.5.7 Touchscreen Mode 11—Auto
Touchscreen mode 11 auto is also used for touchscreen-controlled X/Y coordinate and auxiliary channel
measurement. The difference with the mode 11 single round is that the touchscreen press duration may be
used to control the number of conversions.
Figure 22-19 and Figure 22-20
MODE = 11, and AUTO = 1. The following example with MIDLECNT ≠ 0, RIDLECNT ≠ 0, AZE = 1,
PENE = 1.
22-24
Pen X M
AZX
det ect i on M easur e I DLE
e
b c
d
Figure 22-18. Mode 11 Single Round
illustrate a typical operation sequence when TSE = 1, CALA = 0,
MCF52277 Reference Manual, Rev. 1
Y M U
i
AZY
M easur e I DLE M easur e
NOTE
M U Pen Pen
1
I DLE M easur e det ect i on det ect i on
f
h
g i
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