BitsyXb - User Manual
24
110118-0001A
RTC NVRAM
The real-time clock chip includes 56 bytes of non-volatile RAM. The RAM is maintained as long
as main or backup power is provided to the chip. Drivers are not yet available to access this
feature. Contact Eurotech Sales if your application requires this feature.
4.1.4
Interrupts
The BitsyXb includes several sources for external interrupts. The following table summarizes the
external interrupt sources and the devices to which they are connected.
Interrupt Signal
Pin
IRQ Handler
/RQONOFF
J3.45
PXA270, GP 0
(via CPLD)
CARDBIRQ
J9.27
[tbd]
/EXT_IRQ1
J10.1
PXA270, GP 10
/EXT_IRQ2
J10.3
PXA270, GP 9
/EXT_IRQ3
J10.35
PXA270, GP 1
EIOn
J3, J10
PXA270
Your operating system may not include drivers for all interrupt sources.
4.1.5
CompactFlash / Expansion Bus
The BitsyXb makes its CompactFlash bus signals available on J9. These signals can be used to
add a CompactFlash socket to a daughter board or to expand the capabilities of the BitsyXb as a
digital expansion bus.
The Eurotech Bitsy CF and Ethernet Personality Boards use this bus for CF and digital expansion,
respectively. The schematic (Eurotech document number 640111-8000, available on the Eurotech
Support Forums) illustrates how to use this bus both ways.
4.1.6
PXA270 GPIO Cross-Reference
The following table describes how the BitsyXb utilizes the processor GPIO lines (
GPn
). They are
offered for reference purposes only. Most operating systems make this information transparent to
developers.
GP
Signal Name
Type
Function (connector, section)
0
Wakeup input
from CPLD
I
wakeup from ADSmartIO
1
/EXT_IRQ3
I
External interrupt 3 (4.1.4)
2
3
I2C_SCL
IO
I
2
C bus
4
I2C_SDA
IO
5
P
power supply capacitors for sleep/deep sleep
6
P
7
P
8
P
9
EXT_IRQ2
I
External interrupt 2 (4.1.4)
10
EXT_IRQ1
I
External interrupt 1 (4.1.4)
11
tp
12
CPLD_CLK
13
tp [tbd]
14
SSP_FRM
touch panel
