Rabbit RabbitCore RCM3209 User Manual page 30

Table 2. RCM3209/RCM3229 Pinout Configurations (continued)
Pin Pin Name
20 PG7
21 PG6
22 PG5
23 PG4
24 /IOWR
25 /IORD
SMODE0,
26–27
SMODE1
28 /RESET_IN
29 VRAM
30 VBAT_EXT
31 +3.3V
32 GND
33 n.c.
34 GND
Notes
1. When using pins 33–34 on header J61 to drive LEDs, you must use an external buffer
to drive these external LEDs. These pins are not connected on the RCM3229, which
does not have the LEDs installed.
2. The VRAM voltage is temperature-dependent. If the VRAM voltage drops below about
1.2 V to 1.5 V, the contents of the battery-backed SRAM may be lost. If VRAM drops
below 1.0 V, the 32 kHz oscillator could stop running. Pay careful attention to this volt-
age if you draw any current from this pin.
24
Default Use
Input/Output RXE
Input/Output TXE
Input/Output RCLKE
Input/Output TCLKE
Output
Input
(0,0)—start executing at address zero
(0,1)—cold boot from slave port
(1,0)—cold boot from clocked Serial Port A
SMODE0 =1, SMODE1 = 1
Cold boot from asynchronous Serial Port A at
2400 bps (programming cable connected)
Input
Output
3 V battery Input
Input
Alternate Use
Serial Port E
Serial Clock E input
Serial Clock E ouput
External write strobe
External read strobe
Also connected to
programming cable
Input to Reset Generator
See Notes below table
Minimum battery
voltage 2.85 V
3.15–3.45 V DC
Reserved for future use
RabbitCore RCM3209/RCM3229
Notes