HV3 can also be reconfigured as a sinking output. To do so, remove the 0 Ω surface- mounted resistor R56, and solder on a 0 Ω surface-mounted resistor or jumper wire at R55. If you plan to drive inductive loads, add a diode at D21. Figure 8 shows the location of these components.

 

J5

 

GND

VCC

 

RXC

RXB

 

TXC

TXB

 

PC1

PC0

 

PC3

PC2

 

PC5

PC4

 

PC7

PC6

 

AGND

AD0

 

DA1

DA0

 

PD1

PD0

 

PD3

PD2

 

PD5

PD4

 

PD7

PD6

 

GND

GND

 

485+

485–

 

VCC

VCC

 

SM1

SM0

Battery

STAT

IOBEN

VBAT

GND

 

GND

/RST

 

 

 

J4

 

VCC

GND

 

PA1

PA0

 

PA3

PA2

 

PA5

PA4

 

PA7

PA6

 

GND

GND

 

PB1

PB0

 

PB3

PB2

 

PB5

PB4

 

PB7

PB6

 

PCLK

WDO

 

PE7

GND

 

PE5

PE6

C27

PE3

PE4

GND

PE0

D24

PE1

PE2

HV1

HV0

 

HV3

HV2

 

+RAW

K

 

VCC

GND

R55

R56

D21

Figure 8. Changing HV3 to a Sinking Output

3.2.3 Bidirectional I/O

The Jackrabbit has 14 CMOS-level bidirectional I/O: PA0–PA7, PD0, PD3, PD6–PD7, and PE4–PE5. The BL1820, which does not have RS-485, has one additional bidirectional I/O, PD5.

20

Jackrabbit (BL1800)

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Image 24
Digi BL1800 user manual Bidirectional I/O, Changing HV3 to a Sinking Output