VME-PPG32

VME-NIMIO32 - general purpose VME FPGA board

References

• [1] VME-NIMIO32 (REA 131) project page on edev.triumf.ca
• [2] Rev0 board schematics
• [3] Rev1 board schematics
• [4] Svn repository for VME-NIMIO32 firmware
• [5] Misc documentation

General characteristics

Available hardware

• Altera cyclone 1 FPGA: EP1C6Q240C6N
• Serial flash for FPGA configuration: Altera EPCS16
• External SDRAM memory
• VME interface: VME-D[31..0] bidirectional, VME-A[19..0] input only, DTACK output, no BERR, no RETRY/RESP. VME-A[31..20] input only connected only to address decoder FPGA (Altera MAX-something CPLD). This permits all single-word transfer modes, 32-bit DMA (BLT32) and 2eVME DMA (only drives D-lines, but still faster than BLT32). 64-bit DMA (MBLT64) and 2eSST are impossible.
• 16 NIM outputs
• 16 NIM inputs
• 16 ECL/LVDS inputs compatible with LeCroy 4616 ECL/NIM/ECL converter. (Except: Rev0 boards have an incompatible ECL connector)
• 16 "red" and 16 "green" LEDs
• 1 "VME access" LED
• 1 RJ-45 high speed serial I/O interface

Firmware functions

Generic IO32 firmware can include a number of functions. Not all functions are available all at the same time due to resource limitations on the FPGA. Refer to VME Registers for detailed information.

• 20 MHz 32-bit timestamp clock register
• 16 bits of NIM output register (first 4 NIM outputs are multi-function)
• 16 bits of NIM and 16 bits of ECL/LVDS input register with latch function.
• 32 scalers 32 bit, up to 300 MHz counting rate
• 4 timestamp registers using the 20 MHz timestamp clock. Any of the 32 inputs can be routed into any of the 4 timestamp registers.
• experimental 4-channel TDC. 10 ns base clock with 0.3 ns interpolation ladder (1 ns RMS).

Firmware revisions

To find out the current firmware revision, read VME register 0, i.e. run "test_VMENIMIO32_gef.exe --addr 0xN00000 --read 0".

To write Cyclone 1 FPGA firmware into the flash memory, use a JTAG programmer or a VME programmer: "srunner_vme_gef.exe -program -64 ~/daq/VME-NIMIO32/VME-NIMIO32/VME-NIMIO32/VME-NIMIO32.pof 0xN00020", where "N" is the A24 VME base address.

To reboot the Cyclone 1 FPGA into the new firmware, run "test_VMENIMIO32_gef.exe --addr 0xN00000 --read 0 --write 1 2 --read 0 --sleep 1 --read 0", where "N" is the A24 VME base address. This requires firmware 0x01100810 or newer and the "fpga-reset" hardware modification.

Firmware for the main FPGA:

• firmware sources [[6]]
• 0x01100810 - DO NOT USE - first revision of generic firmware
• 0x01100818 - [[7]] - fixed bug in scaler[6], rearranged TSC4 registers.

Firmware for the VME address decoder:

• firmware sources [[8]]
• board Rev0 [[9]]
• board Rev1 [[10]]

Manual

VME interface

Firmware 0x01100810 implements VME A24/D32 access only. A24 addresses 0x00N0xxxx are decoded, where "N" is the A24 base address set by rotary switch SW3 "ADDRESS 20-23". Rotary switches SW1 and SW2 should be set to "0".

VME accessible registers are listed in the table below. VME address offsets are register numbers multiplied by 4, i.e. CSR register 1 is at address 0x00N00004. Flash programmer register 8 is at 0x00N00020 (use this address with srunner_vme flash programmer).

Registers

Number	Name	Access	FwRev	Description
0	FwRev	RO		Firmware revision
1	CSR	RW	0x01100818	bit 0 - general reset, bit 1 - FPGA reconfigure
2	NIM output	RW		NIM output control: bits 15..0: NIM outputs, 31..16: NIM output function control, see below
3	NIM input	R		bits 15..0: status of NIM inputs, bits 31..16: latched NIM inputs
		W		bits 15..0: reset latch for corresponding NIM inputs (0xFFFF resets latch for all 16 bits
4	example 1	RW		example 32-bit read-write register
5	example 2	RW	0x01100810	bits 15..0 control example scaledown, bits 31..16 control example delay, see NIM output function control
6	timestamp	R	0x01100810	on read, reads the timestamp clock and latches the 32 input scalers (causing scaler deadtime. FIXME!!!)
		W	0x01100810	on write, clears the 32 input scalers
7	LVDS input	RW		ECL/LVDS inputs, works same as register 3
8	Flash programmer	RW		controls the 0xABCD ASMI Flash programmer. For use with "srunner_vme".
9	TDC4	RW		experimental 4 channel TDC. on read, reads the TDC FIFO. on write, resets the TDC.
10	TSC4 routing	RW	0x01100818	Controls signal routing for the 4 TSC units: bits 0..4 select one of the 32 channels routed into TSC[0], 5..10 for TSC[1], and so forth.
11	TSC4 fifo data	RW	0x01100818	Write: TSC4 reset (data fifo, etc). Read: reads the TSC4 data FIFO.
12	TSC4 control	W	0x01100818	on write: writes 32 bits of tsc_control
		R	0x01100818	on read: bits 14..0 - number of words in the TSC4 data fifo, bit 15 - TSC4 FIFO overflow latch (cleared by TSC4 reset), bits 31..16 - readback of tsc_control[31..16]
13	Serio control	R	0x01100818	on read: bit 0 - SMB_SCK, bit 1 - SMB_SDA output, bit 2 - SMB_SDA output enable, bit 3 - SMB_SDA input, bit 4 - SER_TX_LOCKn, bit 5 - SER_RX_LOCKn, bit 6 - SER_RX_CLK, bits 20..16 - SER_RX[4..0]
		W	0x01100818	on write: bit 0 - SMB_SCK, bit 1 - SMB_SDA output, bit 2 - SMB_SDA output enable, bit 6 - SER_TX_CLK, bits 12..8 - SER_TX[4..0]
14	SDRAM control	RW	0x01100818	Writes 32 bits of sdram_cmd: bits 23..0 - ADDR, 26..24 - CMD, 27..28 - DM
15	SDRAM data	RW	0x01100818	Write: low 16 bits of SDRAM input data, Read: bits 15..0 - read back 16 bits of SDRAM input data, bits 31..16 - 16 bits of SDRAM output data.
16..31	NIM scalers	R		read the latched value of NIM input scalers
32..47	LVDS scalers	R		read the latched value of LVDS input scalers
47..64	unused

Functional units

NIM and LVDS/ECL Inputs

There are 16 NIM inputs via LEMO connectors on the front panel and there are 16 LVDS/ECL inputs via a 34-pin header connector on the board. This 34-pin connector is compatible with the LeCroy 4616 NIM-to-ECL converter.

Inside the FPGA firmware, inputs are split into 4 groups:

• NIM_IN/LVDS_IN are the renamed/renumbered input pins;
• NIM_IN_LATCH/LVDS_IN_LATCH are the latched input pins - input transition from 0 to 1 sets the latch bit to 1. latch bits are reset back to zero by writing to a VME register;
• NIM_IN_SYNC/LVDS_IN_SYNC are the input signals synchronized with the 100 MHz system clock. This incurs a 20-30 ns delay (FIXME: need confirmation!) and introduces a 10 ns jitter relative to the unsynchronized NIM_IN/LVDS_IN signals;
• NIM_IN_PULSE/LVDS_IN_PULSE are the synchronized signals with pulse length reduced to 1 clock.

There are 2 VME registers to control the inputs - one for NIM inputs, one for LVDS/ECL inputs. Reading the register returns 16 bits of NIM_IN/LVDS_IN (unsynchronised) and 16 bits of NIM_IN_LATCH/LVDS_IN_LATCH. Writing a 16-bit bit pattern clears the corresponding latch bits, i.e. write of 0x0000FFFF will clear all latch bits, write 0x00000001 will clear only the first latch bit.

NIM Outputs

There are 16 NIM outputs via LEMO connectors on the front panel of the module. Depending on firmware version, they can have arbitrary functions.

In the base firmware, the 16 NIM outputs are connected to the lower 16 bits of the VME NIM output control register. In addition, the first 4 NIM outputs can have multiple functions selected by the upper 16 bits of the NIM output control register.

Upper 16 bits of the NIM output control register select the function of the output according to this table. The function bits are:

• FP_NIMOUT[0] - 0x00030000 - bits 17,16
• FP_NIMOUT[1] - 0x000C0000 - bits 19,18
• FP_NIMOUT[2] - 0x00300000 - bits 21,20
• FP_NIMOUT[3] - 0x00C00000 - bits 23,22

Output	FwRev	Func	Description
FP_NIMOUT[0]	0x01100818	0	nimout[0]
	0x01100818	1	clock 20 MHz - for use as VF48 clock
	0x01100818	2	NIM_IN_LATCH[0] - for use as "daq busy" latch
	0x01100818	3	NIM_IN_LATCH[0]
FP_NIMOUT[1]	0x01100818	0	nimout[1]
	0x01100818	1	NIM_IN_LATCH[1] - for use as "daq busy" latch
	0x01100818	2	pll1_50MHz clock
	0x01100818	3	pll1_50MHz clock
FP_NIMOUT[2]	0x01100818	0	nimout[2]
	0x01100818	1	scaledown2 - prescaler of NIM_IN[2]
	0x01100818	2	scaledown2
	0x01100818	3	scaledown2
FP_NIMOUT[3]	0x01100818	0	nimout[3]
	0x01100818	1	delay3 - delay generator of NIM_IN_PULSE[3]
	0x01100818	2	delay3
	0x01100818	3	delay3
FP_NIMOUT[15..4]	0x01100818		nimout[15..4]

Scalers

The base firmware design allows for 32 scalers, one for each of the inputs. Each scaler is implemented as a 32-bit LPM_COUNTER clocked by the corresponding asynchronous NIM_IN/LVDS_IN signal. The maximum counting rate is limited by the switching time of the synthesized FPGA LPM_COUNTER and can change between different firmware revisions. For each revision, the maximum counting rate corresponds to the "Fmax" value reported by the Quartus FPGA compiler.

To permit accurate measurement of counting rates, readout of scalers is done in conjunction with the timestamp counter. First one should read the VME timestamp register; this will latch the values of all scalers into the VME registers, ensuring all scalers are "read at the same time"; then one should read the 32 VME scaler registers. To compute counting rates, one should divide the increment of the scaler counters by the increment of the timestamp clock counter. For more information and for a code example, please refer to the "software" section.

Scaler counting is inhibited for 3 clock counts (30 ns) while latching scaler data into VME registers. This is done to avoid data corruption if an input signal increments the LPM_COUNTER at the same time as it's contents is being latched into the VME register. Deadtime-less scaler readout requires more FPGA resources and is not implemented in the base firmware. It can be implemented by special request.

Due to FPGA space limitations, the base firmware design does not actually implement all 32 scalers. Actually availble scalers are:

• 0x01100818 - 16 32-bit scalers for LVDS, 4 32-bit scalers for NIM (only the first 4 channels). Fmax is 300 MHz

TSC4

TBW

TDC4

This function is experimental and not available for general use.

Example scaledown (prescaler)

The example scaledown (prescaler) is connected to NIM input 2 and is controlled by the lower 16 bits of VME register 5. The output of the scaledown can be routed to NIM output 2 (see NIM output functions). Scaledown value 0 makes the output follow the input. Value 1 makes the output skip 1 input pulse (scale down factor of 2), value 2 makes the output skip 2 input pulses (scale down factor of 3), and so forth.

Example delay generator

TBW

SOFTWARE

test_VMENIMIO32.exe

Command line switches:

• --addr 0x00N00000 - module A24 base address, N is the setting of rotary switch SW3 "ADDRESS 20-23"
• --read MMM - read register MMM, i.e. "--read 0" reads the firmware revision
• --write MMM VVV - write value VVV into register MMM, i.e. "--write 1 0" writes 0 to the CSR
• --readscalers - read the 32 input scalers, print scaler value, counting rate using the 20 MHz timestamp clock and counting rate using the computer clock.
• --pulsenim - pulse all NIM outputs
• --sleep SSS - sleep SSS seconds, i.e. "--sleep 1" sleeps for 1 second.
• --readtsc - example reading TSC register
• --readtsc4 - example reading and decoding the TSC4 data, programming TSC4 routing

Board modifications

Rev0 modifications

• none

Rev1 modifications

• fpga-reset-mod

K.O.