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1x ESMT M12L64322A 2M 200MHz SDRAM (organized as 4 x 512k x 32bit) (datasheet)
12x 74HC245T Octal Bidirectional Transceiver (used for level translation to 5V)
PCB overview
Definitions
Power
The maximum voltage at the 5V input is 5.5V, due to the buck converters used.
The 5V rail directly feeds only the FPGA power supplies and the 74HC245T output level shifters.
FPGA power is supplied by 3 buck converters. They are compatible with a TI TLV62565/6 in a SOT23-5 package.
Buck converter
Vout
Rail
Description
U34
1.1V
Vcc
Core supply voltage
U37
1.0V
Vref
Reference voltage
U38
3.3V
Vccio
I/O Driver supply voltage and 3.3V for the rest of the board
JTAG
JTAG is available on a 4-pin header next to the FPGA (U33). VCC/GND are available on a 2-pin header nearby.
Pin
Function
J27
TCK
J31
TMS
J32
TDI
J30
TDO
J33
3.3V
J34
GND
SPI Flash (U31)
Flash Pin
FPGA Pin
Function
Notes
1
N8
CS#
2
T7
SO
3
na
WP#
Wired to 3v3
4
na
GND
5
T8
SI
6
FIXME
SCK
7
na
Hold#
Wired to 3v3
8
na
VCC
Wired to 3v3
Connections
Clock
A 25 MHz clock is generated by phy1 (U13) and distributed to phy0 (U11) and FPGA (U33) pin P6.
NOTE: Do not reset the phy(s) if your gateware depend on clock on pin P6
LED, Button
There is a general purpose, FPGA controlled LED (DATA_LED-) at T6, active low (FPGA pin should be set to open drain).
Additionally, there is a button (R7, KEY+).
PAD N16 -> unpopulated R26
SDRAM U29
The SDRAM is organized as 2Mx32.
SDRAM Signal
FPGA Pin for U29
Notes
DQ0
B2
DQ1
A2
DQ2
C3
DQ3
A3
DQ4
B3
DQ5
A4
DQ6
B4
DQ7
A5
DQ8
E7
DQ9
C6
DQ10
D7
DQ11
D6
DQ12
E6
DQ13
D5
DQ14
C5
DQ15
E5
DQ16
A11
DQ17
B11
DQ18
B12
DQ19
A13
DQ20
B13
DQ21
A14
DQ22
B14
DQ23
D14
DQ24
D13
DQ25
E11
DQ26
C13
DQ27
D11
DQ28
C12
DQ29
E10
DQ30
C11
DQ31
D10
BA0
B7
BA1
A8
A0
A9
A1
B9
A2
B10
A3
C10
A4
D9
A5
C9
A6
E9
A7
D8
A8
E8
A9
C7
A10/AP
B8
DQM0
na
Wired to GND
DQM1
na
Wired to GND
DQM2
na
Wired to GND
DQM3
na
Wired to GND
WE#
B5
CAS#
A6
RAS#
B6
CS#
na
Wired to GND
NC
A7
CKE
na
Wired to 3.3V
CLK
C8
Gigabit PHYs (U11 & U13)
PHYRstB, MDC and MDIO are shared between phy0 and phy1.
PHY Signal
FPGA Pin for U11
FPGA Pin for U13
Notes
PHYRstB
R6
R6
MDC
R5
R5
MDIO
T4
T4
TXD3
R1
K15
TXD2
P1
J14
TXD1
M1
J15
TXD0
M2
K16
TXCTL
L2
K14
TXC
L1
J16
RXD3
K3
L16
PhyAddr0
RXD2
K1
L15
PllOff
RXD1
J3
R16
TXDly
RXD0
K2
M15
RXDly
RXCTL
J2
P16
PhyAddr1
RXC
J1
M16
PhyAddr2
INTB
na
na
HUB75 headers
It is possible to replace the 74HC245T output drivers with pin-compatible SN74CBT3245A octal fet bus switches to allow for bidirectional I/O. Note that the output drivers are powered from 5V, so the only protection when using 5V I/O are the resistor packs. ECP5 FPGA does not have 5V tolerant I/O.