Table 2-14. Gc Register; Table 2-15. Gc Fields; General Configuration Register (Gc) - Sharp LH79524 User Manual

Analog-to-Digital Converter/Brownout Detector

2.2.2.6 General Configuration Register (GC)

In this register, the SSM field triggers the state machine to retrieve the data from the
Control Bank and store it in the appropriate registers for the ADC. If the SSM bits are set
to 0b11 at the end of a sequence, the state machine continues to convert data.
If the SSM bits are set to 0b10 and a value of 0b0000110 is written to the GC Register, the
EOS_UM bit (bit [2]) of the Interrupt Status Register may never get set. This is normal
operation. To accommodate this, wait two A2DCLK periods after setting the SSM bit to 10
before setting the SSB bit.
NOTE: Allow two A2DCLK cycles between successive write cycles to this register. Otherwise, ADC behavior
BIT
FIELD
RESET
RW
BIT
FIELD
RESET
RW
ADDR
BIT
31:7
6:3 FIFOWMK
2
1:0
2-18
can become erratic.
31 30 29 28 27
0 0 0 0
RO RO RO RO RO
15 14 13 12 11
0 0 0 0
RO RO RO RO RO
NAME
/// Reserved Reading returns 0. Write the reset value.
FIFO Watermark Programmed to values between 0 and 15. This value
corresponds to watermark levels between 1 and 16, respectively. When
the FIFO fills to this level, the FIFO generates an interrupt.
Start Sequence Bit
SSB
1 = SSB will start the conversion sequence
0 = SSB will not start the conversion sequence
Sequence Start Mode To trigger continuous conversions, set these bits
to 0b11, wait one A2DCLK period, and set the SSB bit to 1. Thereafter,
once any conversions occur and SSM is set to 0b00 to stop the conversions,
conversions can be started again by setting SSM to 0b11, without having to
set SSB.
SSM Note that the Pen Interrupt can only be used when the ADC is configured to
start on Pen Down.
00 = SSB or Pen Interrupt starts new conversions
01 = Pen Interrupt starts new conversions
10 = SSB starts new conversions
11 = Continuous conversions

Table 2-14. GC Register

26 25 24 23
///
0 0 0 0 0
RO RO RO RO
10 9 8 7
///
0 0 0 0 0
RO RO RO RO
0xFFFC3000 + 0x14

Table 2-15. GC Fields

DESCRIPTION
Version 1.0
LH79524/LH79525 User's Guide
22 21 20 19 18
0 0 0 0 0
RO RO RO RO RO
6 5 4 3 2
FIFOWMK SSB
0 0 0 0 0
RW RW RW RW RW
17 16
0 0
RO RO
1 0
SSM
0 0
RW RW