5.1. DUT Communication Module

This module controls the communication with the Device Under Test (DUT) and determines from the handshaking lines what the state of the DUT is.

5.1.1. DUT Interface

The DUT interface consists of reset, clock, data, and handshaking signals. The FOBOS Shield can also provide power to the DUT. All signal names start with the letter F for FOBOS. The next letter tells where the signal originates: C for control board, D for DUT. Bidirectional signals always get a C. For example FC_RST is a reset signal that gets send by the control board; FD2C_HS is a handshaking signal that goes from the DUT to the control board.

5.1.1.1. Pynq Controller with FOBOS Shield

The FOBOS Shield provides a FOBOS target connector which is compatible to the ChipWhisperer target connector. The FOBOS target connector is shown in Fig. 5.2 and the pin-out is described in Table 5.1. LOC is the FPGA pin name. This is a 4-bit half-duplex FIFO interface.

Fig. 5.2 FOBOS target connector viewed from front

Table 5.1 FOBOS target connector Pinout

Pin	LOC	Net	CW Name	Comment
1		FC_5V		5V Supply
2		GND
3		FC_3V3		3.3V Supply
4	U7	FD2C_CLK	CS_HS1	Clock from DUT to Control
5	T14	FC_RST	CW_RST	DUT Reset
6	Y7	FC2D_CLK	CS_HS2	Clock from Control to DUT
7	U5	FC_IO	CW_MISO	Direction of Bus
8		FD_VREF		IO Voltage of DUT
9	V5	FD_TF	CW_MOSI	DUT Busy
10	U12	FC_DIO0	CW_TARG1	Data Bus bit 0
11	V6	FC2D_HS	CW_SCK	Control to DUT Handshaking
12	U12	FC_DIO1	CW_TARG2	Data Bus bit 1
13	V15	FD2C_HS	CW_PDIC	DUT to Control Handshaking
14	U12	FC_DIO2	CW_TARG3	Data Bus bit 2
15	T15	FC_PROG	CW_PDID	DUT Programing
16	U12	FC_DIO3	CW_TARG4	Data Bus bit 3
17		GND
18		FC_3V3		3.3V Supply
19		GND
20		FC_5V		5V Supply

5.1.2. Setting DUT Interface

FOBOS supports a 4-bit full-duplex FIFO interface when using PMOD connectors and a 4-bit half-duplex FIFO interface when using the target connector on the FOBOS Shield. The selections are:

• INTERFACE_4BIT: 4-bit half-duplex FIFO interface using the target connector on the FOBOS Shield

• INTERFACE_8BIT: 4-bit full-duplex FIFO interface using PMOD connectors

ctrl.setDUTInterface(FOBOSCtrl.Value)

5.1.3. Output Length

FOBOS has to know how may output Bytes it has to expect from the DUT. This is used to generate the tlast signal used to mark the end of the packet.

ctrl.setOutLen(Value)