Cypress OSM-CPI OSDP Interface

Power can be supplied to the OSM-CPI by either the red and black flying leads, or pins 1 and 2 of the terminal block. These connections are common, and are intended to be used to pass power through the OSM-CPI from the flying leads to a peripheral device connected to the terminal blocks. Do not connect two sepatate power supplies to these connections. The OSM-CPI power requirements are 6-30Vdc, 50mA typical (200mA max).

RS-485

The OSM-CPI uses the DS3695 RS-485 transceiver to interact with the RS-485 bus and to communicate with other OSDP compliant devices. The OSM-CPI supports communication speeds of 9600, 19200, 38400, 57600, and 115200 bits per second, and defaults to 9600 bps. The communication speed can be changed by issuing an osdp_COMSET command to the OSM-CPI in PD mode. The RS-485 B and A signals are connected to the terminal block pins 3 and 4, respectively.

Wiegand

The OSM-CPI’s Wiegand output D0 and D1 signals are connected to the green and white flying leads, respectively. The Wiegand outputs are open-collector NPN transistors, pulled up to 5 volts internally through diodes and 680Ω resistors. Wiegand transmissions are nominally 1000 bits per second, with a pulse-off time of about 100 µs. The OSM-1000 can handle between 1 and 255 bits of Wiegand, and handles special cases for 8 bit burst keypad readers.

Other Digital I/O

The OSM-CPI has two dedicated digital inputs, two signals that can be either inputs or outputs, depending on configuration, and two dedicated analog inputs. In the default configuration, the brown and orange flying leads are inputs that control the PD’s LED, the blue flying lead is an input that controls the PD’s buzzer, the yellow flying lead is an output that indicates tamper, and the purple and grey flying leads are analog inputs used for configuration.