I am trying to develop a product with your nRF905. I have two units set up, and can read and write via SPI. However my concern is your poor documentation.
You do not say which registers are stored through power down. From experimentation I have discovered that TX and RX addresses are not stored in power down, but other registers are.
In your documentation, the layout of the registers is poor, and there are errors. For instance on page 19 Table 9. You refer to CH_NO as being 9 bits wide, when in fact it is 1 8 bit register and a bit in another register. This same confusion is in Table 10 as well, in the byte 1 entry, where it is not immediately clear that the channel number is 9 bits.
It would be helpful to lay out each register fully in a table of bit positions, e.g.
| BYTE 0 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| Contents | CH7 | CH6 | CH5 | CH4 | CH3 | CH2 | CH1 | CH0 |
| BYTE 1 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| Contents | XX | XX | AUTO RETRAN | RX_RED POWER | PAPWR1 | PAPWR0 | HFPLL | CH8 |
Funnily enough, it was while laying out this fraction of table that I realised why you are referring to a 9 bit Channel number!
Currently I have the transmitter which appears to be working, but I get no response from the receiver. But I now know that I have to write the configuration register on powerup, and also the TX address if I wish to customise it, on power up. This information should be in the documentation. Also the documentation implies I can read the SPI with the receiver powered up, but is this in fact the case? Elsewhere the documentation says that the SPI is only enabled with the receiver and transmitter disabled.
When working with complex devices it is vital that the documentation is accurate. Otherwise developers have to spend many hours working out the mistakes.
