Sharp LH79524 - General Status Register (GS); Table 2-16. GS Register; Table 2-17. GS Fields

LH79524/LH79525 User’s Guide Analog-to-Digital Converter/Brownout Detector
Version 1.0 2-19
2.2.2.7 General Status Register (GS)
GS is the General Status Register. In this Read Only register, the 4-bit signal CBSTATE
field shows the current state of the Control Bank state machine. The CBTAG signal con-
tains the control bank entry number of the conversion that is taking place.
NOTE: *If the Idle state is configured to bias a 4-wire Touch Screen for Pen IRQ detect, the PENIRQ bit is
only set during the one A2DCLK period of the GET_DATA state. To determine if the pen has been
down at all, examine the IS:PENSYNC_UM bit. To determine if the pen was down at both the start
and the end of a measurement sequence, use analog measurements of the pen IRQ voltage at the
beginning and the end of the sequence. Then have a software Schmidt Trigger verify the logic level
at the beginning and end of the coordinate-measurement sequence. Install a Pen IRQ handler func-
tion that changes the measurement mode to software triggered and disables Pen IRQ interrupts.
Then stop the timer when it expires. Next, install an end-of-sequence interrupt handler that reads the
measurement results and determines whether the pen is still down. If the pen is down, the handler
starts the timer for triggering the next measurement. The handler discards the first set of measure-
ments taken during the initial Pen Down detection. Otherwise, the handler posts the current pen posi-
tion to some sort of OS queue. Enable Pen Triggered Measurements to start the system.
Table 2-16. GS Register
BIT 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
FIELD ///
RESET 0000000000000000
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 ///
BRONOUT
PENIRQ
CBSTATE CBTAG
RESET 0000001000010000
RW RO RO RO RO RO RO RO RO RO RO RO RO RO RO RO RO
ADDR 0xFFFC3000 + 0x18
Table 2-17. GS Fields
BIT NAME DESCRIPTION
31:10 /// Reserved Reading returns 0. Write the reset value.
9 BROWNOUT
Brown-Out Raw Interrupt Status
1 = Brown-out Interrupt is active.
0 = Brown-out Interrupt is not active.
8 PENIRQ*
Pen IRQ Raw Interrupt Status
1 = Pen IRQ Interrupt is active.
0 = Pen IRQ Interrupt is not active.
7:4 CBSTATE
Control Bank State Machine Status The only valid values are:
0001 = Idle state; waiting for sequence start trigger
0010 = GET_DATA state
0100 = WAIT_CONV state
1000 = END_OF_SEQ state
3:0 CBTAG
Current Conversion Tag Number Contains the current conversion tag
number.