SU750
Contents
SU750 pin table (direction shown for the SU board!)
power in +5V 2 1 +5V in power LVTTL bidir SDA 4 3 SCL in LVTTL LVTTL out DATA<1> 6 5 DATA<0> out LVTTL LVTTL out DATA<3> 8 7 DATA<2> out LVTTL LVTTL out DATA<5> 10 9 DATA<4> out LVTTL LVTTL out DATA<7> 12 11 DATA<6> out LVTTL LVTTL out DATA<9> 14 13 DATA<8> out LVTTL LVTTL out DATA<11> 16 15 DATA<10> out LVTTL LVTTL out DATA<13> 18 17 DATA<12> out LVTTL LVTTL in TRIGG 20 19 VALID out LVTTL LVTTL in FREQ<2> 22 21 SPI_CONF in LVTTL LVTTL in FREQ<1> 24 23 FREQ<0> in LVTTL LVTTL in RESET 26 25 CLK_READ in LVTTL LVTTL out SDRD 28 27 SEn in LVTTL LVTTL in SCLKn 30 29 SDATA in LVTTL LVTTL out PGND<1> 32 31 PGND<0> out LVTTL LVTTL in CLKp 34 33 CLKn in LVTTL power in GND 36 35 GND in power
Differences to SU735:
ADC
SU735 SU750 LTC2261 ADS4149
Pinout
SU735 SU750 PIN GI_GATE (in) VALID (out) 19 SPARE<1> TRIGG (in) 20 SPARE<2> SPI_CONF (in) 21 SPARE<3> FREQ<2> (in) 22 (still not used in design) CLK_CPU CLK_READ 25 (was not used in the latest firmware of SU735) - GND 31, 32
Clocks
- CLKp, CLKn
SU750 should get ALWAYS 100 MHz at CLKp and CLKn! The SiLabs PLL creates depending on the two FREQ pins four frequencies for the ADC:
FREQ[1:0] Frequency, MHz 0 100 1 150 2 200 3 250
- CLK_READ can be 100 MHz or below, it is used to clock out the data from the internal memory
Output data:
VALID = 1 means valid output data (SU750), SU735 forwards directly the ADC data.
Trigger
TRIGG = 1 starts the data storing, shortly after triggering the readout is started as a complete block, with VALID=1 indicatiing valid data.
SPI configuration
SPI_CONF = 1 selects the internal configuration registers instead of the ADC (and disconnects the ADC SPI).
The SPI Word has 16 bits (like of the LT ADC), the upper 3 (MSB) bits are address, the next bit is read(0) or write(1), the other 12 (LSB) bits are data.
SPI configuration registers:
PRESAMPLE (10 bits) at 0
EVNT_SIZE (3 bits) at 1
evnt_size Event Size[samples] 000 16 001 32 010 64 011 128 100 256 101 512 110 1024 111 1024 (later 2048)
LED (7 bits) at 2
Bits 0..4 are for LEDs from top to bottom. Bit 5: when 0, display the "ok" of test pattern check for 0x2AAA -> 0x1555, else LED=Bit 3 Bit 6: when 0, display the "ok" of test pattern check for ramp, else LED=Bit 4
SEND_TP (2 bits) at 3
Bit 1 : when 0 => normal ADC data else testpattern data Bit 0 : when 0 => 0x3FFF -> 0x0000 else 0x2AAA -> 0x1555
This test pattern is send at 100 MHz (CLK_READ) continuously by the FPGA and can be checked in the LogicBox.
FREQ_CNT at 4
Read the ADC clocks for 1000 logic box (CLK_READ) clocks => divide by 10 to get the freq in MHz (provided CLK_READ is 100 MHz).
TP_CHECK at 5
Bit 1 : ok for ramp pattern from ADC Bit 0 : ok for 0x2AAA -> 0x1555 pattern from ADC
This test pattern is send by the ADC and checked continuously in the FPGA for errors. The flags are cleared by any error and can be set by writing anything to this address. So the typical test procedure is 1) set the frequency and test pattern in ADC; 2) wait a bit and clear the errors by writing to TP_CHECK; 3) wait some seconds (or more) and read the two flags.
ADC configuration registers (the most essential)
(for the full description see the datasheet)
The default values of all registers is 0x00
RESET, SDO at 0x00
Bit 1 is RESET (reset the ADC when 1), bit 0 is READOUT (set the SPI interface in read mode)
HIGH PERF MODE 1 at 0x03
Bits 1:0 should be set to 1 for best performance
GAIN, TEST PATTERN
Bits 7:3 control the digital gain, best don't use it (Bit 3 at 1, the rest at 0) Bits 2:0 Output 000 Normal operation (ADC data) 001 All 0s 010 All 1s 011 Toggle pattern, 0x2AAA -> 0x1555 100 Digital ramp (14-bit counter) 101 Custom pattern (use registers 0x3F and 0x40) 110, 111 Unused
