Rabbit RabbitCore RCM3400 User Manual page 93

The RCM3400 Prototyping Board comes with a 220 Ω termination resistor and two 681 Ω
bias resistors installed and enabled with jumpers across pins 1–2 and 5–6 on header JP3,
as shown in Figure B-9.
5 3 1
C5
PA0 PA1
R10
PA2 PA3
C7
PA4 PA5
CX2
UX2
PA6 PA7
PB1 PB2
6 4 2
PB3 PB4
PB5 PB6
PB7 PC0
PC1 PC2 CX1
UX1
PC3 PC6
PC7 /IORD
/IOWR STAT
SMODE1 SMD0
PD0 PD4
485+
PD5 PD6
U3
PD7 PE0
PE1 PE2
U2
PE4 PE5
6
2
PE6 PE7
PF0 PF1 R21
PF4 PF5
C39
PF6 PF7
7
6
PG0 PG1
C28
PG2 PG3
PG4 PG5
PG6 PG7
/RES OUT RESET IN
485–
+3.3 V GND
VBAT +3.3 V
GND GND
C1
C3
IR1
R4
R5
R3
C4
R1
R8
R2
J3
RCM3400
PROTOTYPING
BOARD
GND AIN0 AIN1 AIN2 AIN3 AIN4 AIN5 AIN6 THERM GND CNVRT VREF
Figure B-9. RS-485 Termination and Bias Resistors
For best performance, the termination resistors in a multidrop network should be enabled
only on the end nodes of the network, but not on the intervening nodes. Jumpers on boards
whose termination resistors are not enabled may be stored across pins 1–3 and 4–6 of
header JP3.
User's Manual
C19 C21
U4
C28
R46
C18 C22 C25
C30
U5
PG6
JP8 C23
JP4
C53
C31
PG7
R39 C32
C26
CX3
CX7 CX9
R40
R45
R41
CX4 CX8 CX10
C33
R42
CX5 CX6 CX11
R62 C34
+3.3 V
C35
C36
C37
RESET
R26 1
RP2 RP3 RP4 JP3
JP3 S1
bias
C59
681 W
C56 2
+5 V
C53 C55
C51 C50
1
R24
GND
R67
JP6 R22
termi-
JP7
+3.3 V
220 W
nation
5
R16
bias
681 W
C19
C14
C13
R3
C1 R1
R13
R14
U1
JP1 JP2
GND
+5 V
S2
BT1
Battery
C46
Y1
R54
C41 C42
R59
C52
HOT
C49
C51
C50
U7
U6
DS2
DS1
R47 R57
PD6 PD7
+3.3 V
2 2
GND
S3
1 1
PD4
PD5
+5 V
L1
D2
D1
C61
DCIN
U10 GND
C54
+3.3 V
U12
C55
+5 V +5 V
C56
C59 U13 C60
R64
GND GND
LCD1JA
GND
LCD1JC
LCD1JB
+3.3 V
GND
+5 V
87