RPC-UHF RADIOMETRIX [Radiometrix Ltd], RPC-UHF Datasheet - Page 7

• Manufacturer Part Number: RPC-UHF
• Description: Radio Packet Controller
• Manufacturer: RADIOMETRIX [Radiometrix Ltd]

figure 7: TX download timing diagram
The sequence for a byte transfer from the Host to the RPC (i.e. TX download) is asynchronous and
proceeds as follows:
1. HOST asserts TX Request line low to initiate transfer
2. Wait for RPC to pull TX Accept low (i.e. request is accepted)
3. Set data lines to output and place LS nibble on the data lines
4. Negate TX Request (set to 1) to tell RPC that data is present.
5. Wait for RPC to negate TX Accept (i.e. data has been accepted)
Repeat steps 1-5 with MS nibble.
Notes:
• The data bus must not be set to output until step 3. i.e. after the RPC has accepted the request. The
• The RPC's normal response time to the initial TX Request may be up to 1ms, thereafter, for the
• The RPC will ignore a TX Request from the Host while it is receiving a packet from the radio. If the
• For the above reason it is often easier to use RX Request to trigger a HOST interrupt and upload
• See Appendix B and C. for example RPC driver subroutines.
Radiometrix Ltd, RPC
bus may be left as an output until the entire packet has been transferred to the RPC, it should then
be set back to input (default state).
duration of the packet, the response will be fast.
incoming packet fails it's error check the RPC will respond to the TX Request as normal, i.e. the TX
Accept from the RPC will be delayed until the incoming packet has finished. If a valid packet is
received this must be uploaded to the Host before the RPC can respond to the Host’s TX Request.
Thus an RX Request will be signalled to the Host and not the expected TX Accept and the Host
must upload the incoming packet before the TX packet can be downloaded. The TX Request should
be left asserted (low) during the upload. The RPC will respond as normal after the upload is
completed.
the RPC to the HOST under interrupt control.
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