AK4186 Datasheet, PDF (23/33 Pages) Asahi Kasei Microsystems – Low Power Touch Screen Controller with I2C Interface

[AK4186]
■ Touch Screen Controller Control Sequence (Sequence Mode)
The AK4186 starts A/D conversion in sequence mode by setting the COUNT, SEQM2-0, INTERVAL2-0 bits of the
register address 02H. PENIRQN is forced to “L” state, and internal oscillator is automatically powered up. The AK4186
makes six or ten measurements by setting the COUNT bit. The results are used to calculate the average value,
discarding the minimum and maximum values, and the result sets the data register of sequence mode. When the
sequence is finished, the AK4186 sets the PENIRQN pin to “H” and notifies that sequence is ended. After 20μs (typ.) is
passed from the rising edge of the PENIRQN pin, the internal oscillator is powered down and PEN interrupt function is
enabled.
The master executes the register read operation to read the measurement data of sequence mode after confirming Data
availability. The master can confirm Data availability by PENIRQN↑ or SEQST3-0 = 03H.
This sequence data can be read in register read operation one by one (Address 11H). Prior to issuing the slave address
with the R/W bit “1”, the master must first perform a “dummy” write operation. The master issues start request, a slave
address (R/W bit = “0”) and then the register address to read. After the register address is acknowledged, the master
immediately reissues the start request and the slave address with the R/W bit “1”. The AK4186 then generates an
acknowledge, 1 byte of ADC data, and increments the internal address counter by 1. If the master does not generate an
acknowledge but generates stop condition instead, the AK4186 ceases transmission. The A/D data is cleared after
reading all the A/D data.
Pen
Touch
Sequence Start
Set PENIRQN Low
Start Clock
Driver Set
Wait Timer
ADC
No
Count End?
Yes
Sequence
No
End?
Yes
Set PENIRQN High
Stop Clock & PenTouch Enable
Done
Figure 29. Internal Clock Mode Control Flowchart
MS1068-E-04
- 23 -
2011/03