WIENER Product Discussion

[jtoke]

The newest release of VM-USB firmware is 18000805 (of January 2008). It has two features added with respect to version VMEUSB_0804:

1. Now one can force flush of the scaler buffer immediately after a scaler event and not after a first non-scaler event is detected after scaler event. This feature may be useful in circumstances where the rate of non-scaler events is very low and when one still desires to actively monitor scaler rates. To activate this option, one must set bit 9 (0x200) of the global register to 1. When stack 1 is used for IRQ, one would disable the flush by clearing this bit.

2. One can now insert "wait" periods into the stack readout cycle by inserting "wait" commands into the stack. The "wait" command is a single 32-bit word (2 stack lines, as usual) with bit 15 (0x8000) set. Bits 0-7 of this word represent the desired wait period in steps pf 200 ns, up to 255 steps. For example, to suspend readout for 1us, one would add two lines into the stack:
8005 and 0000 (actually the logic disregards bits other than 0-7 and 15).

Additionally, a bug that creeped in with some earlier release corrupting functioning of BERR issued by an external module has been fixed.
Also, a feature disabled in quite early releases (deemed by me at time redundant) has been restored. This feature flags the scaler buffers by setting bit 14 (0x4000) in the buffer header word. This bit is set generally for buffers generated by executing stack 1, whether this stack is used as a scaler stack or as an IRQ stack.

[Akeemun3322]

Hello...
Thanks for your superb post you gave a very good idea about New VM-USB firmware, VM_0805. Thanks for your good effort. All VM-USB logic is controlled by the XILINX Spartan 3 family FPGA. Upon power-up the FPGA boots from a flash memory. The configuration flash memory can be reprogrammed via the USB port, allowing convenient updates of the firmware.