Datasheet

906
SAM9M10 [DATASHEET]
6355F–ATARM–12-Mar-13
3. Convert Channel X
p
and store the result in both TSADCC_Z1DR and TSADCC_LCDR.
4. Close the switches on the inputs X
M
and Y
P
during the Sample and Hold Time.
5. Convert Channel Y
M
and store the result in both TSADCC_Z2DR and TSADCC_LCDR.
6. Close the switches on the inputs X
P
and X
M
during the Sample and Hold Time.
7. Convert Channel X
M
and store the result in TSADCC_CDR1.
8. Close the switches on the inputs X
P
and X
M
during the Sample and Hold Time.
9. Convert Channel X
p,
subtract TSADCC_CDR1 from the result and store the subtraction result in both
TSADCC_CDR0 and TSADCC_LCDR.
10. Close the switches on the inputs X
P
and X
M
during the Sample and Hold Time.
11. Convert Channel Y
P
and store the result in TSADCC_XPDR, subtract TSADCC_CDR1 from the result
and store the subtraction result in both TSADCC_CDR1 and TSADCC_LCDR.
12. Close the switches on the inputs Y
P
and Y
M
during the Sample and Hold Time.
13. Convert Channel Y
M
and store the result in TSADCC_CDR3 while storing content of TSADCC_XPDR in
TSADCC_LCDR.
14. Close the switches on the inputs Y
P
and Y
M
during the Sample and Hold Time.
15. Convert Channel Y
p
subtract TSADCC_CDR3 from the result and store the subtraction result in both
TSADCC_CDR2 and TSADCC_LCDR.
16. Close the switches on the inputs Y
P
and Y
M
during the Sample and Hold Time.
17. Convert Channel X
p
subtract TSADCC_CDR3 from the result and store the subtraction result in both
TSADCC_CDR3 and TSADCC_LCDR.
18. if Channel 4 to channel 7are enabled, convert the channels and store result in the corresponding
TSADCC_CDRx and TSADCC_LCDR
19. If SLEEP is set, sleep down the ADC cell.
The resulting buffer is 16 bits wide and its structure stored in memory is:
1. Z1
2. Z2
3. X
P
- X
M
4. Y
P
- X
M
5. Xpos
6. Y
P
- Y
M
7. X
P
- Y
M
8. AD4 to AD7 if enabled.
The vertical position can be easily calculated by dividing the data at offset 2 (X
P
- X
M
) by the data at offset 3(Y
P
-
X
M
).
The horizontal position can be easily calculated by dividing the data at offset 5 (Y
P
- Y
M
) by the data at offset 7 (X
P
- Y
M
).
The Pressure measure can be calculated using the following formula
Rp = Rxp*(Xpos/1024)*[(Z2/Z1)-1]
40.10.3 Interleaved Mode
In the Interleaved Mode, the conversion of the touch screen channels are made in parallel to each channel. In addi-
tion to interleaving, the analog channels 4 and 5 can be converted more often than the touch screen channels
depending on the TSFREQ field in the register TSADCC_MR. In the interleaved mode at least one ADC channel
must be enabled.