GPS Free Stack/Notes About Milkymist

Currently using/borrowed address space from the softusb core, later the plan will be properly add a gps baseband slave core.

Namuru core implement its own clock domain, there is just clock sync for the ack wire. It reports ~0.18% of data loss.

Need to confirm:

• fixed or not minimum unit of data transfer that is supported by conbus (hacked wishbone)
• limitations of milkymist libc that can affect basic tracking (report here as soon confirmed)
• additional measurements in clock domain sync (again?)

Interfacing

Currently the SiGe SE4162T-EK is interfaced with the Milkymist One board trought the expasion header J21 and memory card reader test point as follows:

   SE4162T-EK1 EVB                                           Milkymist One    
  J4 Pin 1 VBAT     .................................... J21 Pin 3  3V3 
  J4 Pin 3  SYNC    ------------------------------------ J21 Pin 7  A20 
  J4 Pin 4  DATA    .................................... J21 Pin 9  A21
  J4 Pin 5  CLK_OUT ------------------------------------ TP 19 CLK  A10
  J4 Pin 8  GND     .................................... J21 Pin 17 GND
  J5 ANT  (to active GPS External Antenna)

Clock input is wired to memcard as exp header lacks a dedicated clock route.

SiGE EVB Jumper positions:

 J1 2<->3 Fit
 J9 1<->2 FIT
 R4 0 = 0R

This setup allow the use of the on-board regulator (wich is not the internal LDO from SiGE chip). (LDO still need to be tested) (LNA still need to be tested)

Optional Debug Signals on EVB:

  J4 Pin 10 Vdd  (Expected 2V9~ in normal operation)
  J4 Pin ANT_DET (Expected 3V3~ When External ANT connected)}

Real Mode (current mode) More generic mode, no relay single chip, not saying complex is not better, just lacking support in embedded gps related software so far?

R9 = 47K to R14.