H220 Integrator Guide
Chapter 2 – Board Overview
Page 15 of 28
If used, Port D will free up the task of Port A, B, or C from being used for external correction input.
If you want to support external correction input when the product is in the field, Hemisphere
recommends that you offer the facility to the user to input corrections on Port A, B or C, and that
Port D remain within the integration only.
CAN
A CAN Transceiver is required. The H220 CAN RX and CAN TX are 3.3V CMOS signals. The
H220 connects to the transceiver on the single-ended CMOS port. CANH and CANL are CAN
standard signals on the physical bus side of the transceiver(the H220 does not connect to this
portion of the transceiver).
LED Indicators
The H220 features the following surface-mounted diagnostic LEDs that indicate board status (see
Figure 2-3):
PWR – Power
P-GNSS - Primary GNSS lock
DIFF - Differential lock
DGNSS - DGNSS position
S-GNSS - Secondary GNSS lock
HDG - Heading lock
Figure 2-3: Onboard LEDs
With the exception of the PWR LED the signals that drive the LEDs are available via the header
connector. Refer to Table 2-2 for pin number descriptions for the H220.
1 PPS Timing Signal
The one pulse per second (1 PPS) timing signal is used in applications where devices require
time synchronization.
Note:
DGPS corrections are not required for heading accuracies as specified. External
corrections will only affect positioning performance.
Note:
Each signal pin can offer only 1 mA of current and is active low. Since 1 mA of current
may be inadequate for the application, you may want to transistor-buffer these signals to
provide more current capacity for acceptable LED luminance.
Note:
1 PPS is typical of most GNSS boards but not essential to normal receiver
operation. Do not connect the pin if you do not need this function.
