Analog-to-Digital Converter/Brownout Detector
LH79524/LH79525 User’s Guide
2-18
Version 1.0
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
can become erratic.
Table 2-14. GC Register
BIT
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
FIELD
///
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RW
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
BIT
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FIELD
///
FIFOWMK
SSB
SSM
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RW
RO
RO
RO
RO
RO
RO
RO
RO
RO
RW
RW
RW
RW
RW
RW
RW
ADDR
0xFF 0x14
Table 2-15. GC Fields
BIT
NAME
DESCRIPTION
31:7 ///
Reserved
Reading returns 0. Write the reset value.
6:3 FIFOWMK
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.
2 SSB
Start Sequence Bit
1 = SSB will start the conversion sequence
0 = SSB will not start the conversion sequence
1:0 SSM
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.
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