Command Register

Address = &h000; Read/Write Access

This register is used to direct Tibbit #26 to start receiving IR data or start transmitting IR data. This register also contains three option bits.

• Bit 4, carrier mode: 0 — incoming signal contains the carrier frequency; 1 — incoming signal does not contain the carrier frequency.
• Bit 3, data output mode: 0 — LOW to turn the emitter LED on (normal mode); 1 — HIGH to turn the emitter LED on (inverted mode).
• Bit 2, data input mode: 0 — LOW means that the IR light is detected (normal mode); 1 — HIGH means that the IR light is detected (inverted mode).
• Bit 1: "Rising edge" on this bit directs Tibbit #26 to start receiving data.
• Bit 0: "Rising edge" on this bit directs Tibbit #26 to start transmitting data.

"Rising edge" for bits 1 and 0 refers to the change of the bit state. For example, to initiate data reception in the no-carrier mode, do the following:

• Write &h10 into the command register. This will set bit 4 (carrier mode) to the desired state and clear bit 1.  
• Write &h12 into the command register. This will still keep bit 4 in the desired state and set bit 1 to HIGH. As this bit was previously set LOW, this second step will achieve the "rising edge" on bit 1.

Note that the two writes above are two separate write transactions that sequentially store &h10 and &h12 into the command register.