Abnormal MACRO ring frequency !

[sbrun]

Hello,

With a system with PowerPmac Etherlite (only one Gate3) + 3x GeoMacroDrive.

- Firmware 2.5.0.4, IDE 3.1.4.0

We want Macro-ring and Phase-clock at 16 kHz, Servo-clock 4KHz. We done :

Gate3[0].PhaseFreq = 16000;

Gate3[0].PhaseClockDiv = 0;

Gate3[0].ServoClockDiv = 3;

Gate3[0].PhaseServoDir = 0;

Gate3[0].MacroModeA = $403000;

Gate3[0].MacroModeB = $009000;

Gate3[0].MacroEnableA = $0FC57500;

Gate3[0].MacroEnableB = $1F800000;

 

As soon as downloaded + save + $$$ we got in the task manager :

Phase Freq.: 20 KHz !!! Strange isn't it

Servo Freq.: 5 KHz

 

Solution found :

Gate3[0].MacroModeB = $001000;

and then all is ok: Phase Freq.: 16 KHz, Servo Freq.: 4 KHz

 

Could you explane me why .MacroModeB =$009000 do that problem on the clocks frequency ?

 

Thank you in advance.

[steve.milici]

That value sets the MacroSyncEnaB bit. This bit is not used if the IC is the synchronizing master for the ring, or if it is receiving the phase clock from another IC in the same device.

 

See the description of “Gate3.MacroModeB” in the “Power PMAC Software Reference Manual” for more details.