Touchscreen Mode 10—Auto - Freescale Semiconductor MCF52277 Reference Manual

Touchscreen Controller/Analog-to-Digital Converter
e) ASP begins one round of auxiliary channel measurements, starting with the highest numbered
active channel.
f) ASP completes one round of auxiliary channel measurement and enters the pen-detect state
again. If the FIFO watermark is set to the number of active auxiliary channels, the FIFO
watermark interrupt can be used to upload the conversion results.
g) A pen-up event is detected and the pen-up interrupt occurs. If the FIFO watermark interrupt is
not used, the conversion results may be uploaded here.
h) ASPE is cleared automatically or by MCU depending on the PENE setting. The ASP is ready
to detect the next pen-down event.
i) MCU clears the pen-up interrupt.
If MIDLECNT is equal to zero, remove the IDLE measurement phase.
22.5.5 Touchscreen Mode 10—Auto
Touchscreen mode 10 auto is also used for touchscreen-controlled auxiliary channel measurement. The
difference with the mode 10 single round is that the touchscreen press duration may control the number of
conversions.
Figure 22-16 and Figure 22-17
MODE = 10, and AUTO = 1. The following example assumes MIDLECNT ≠ 0, RIDLECNT ≠ 0,
PENE = 1.
BIACTRL
Pen
SELREFP
SELREFN
det ect i on
SELINP
a
PENDOWN_IRQ
ASPE
FIFO_WM_IRQ
22-22
illustrate a typical operation sequence when TSE = 1, CALA = 0,
Pen U M
n
det ect i on M easur e I DLE
e
b c
d
Figure 22-16. Mode 10 Auto, Part 1
MCF52277 Reference Manual, Rev. 1
NOTE
NOTE
U M U
i 1
M easur e I DLE M easur e
f
g
R Pen U
n
I DLE det ect i on M easur e I DLE
h
Freescale Semiconductor
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