--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/venus/src/usb/FT2232D_block.v	Sat Nov 20 17:48:18 2021 +0000
@@ -0,0 +1,90 @@
+/*
+ * This module encapsulates the FT2232D chip and its immediate accessories:
+ * the oscillator crystal, the EEPROM, the AVCC filter and the cap on 3V3OUT.
+ */
+
+module FT2232D_block (GND, VCC, VCCIOA, VCCIOB,
+		      USBDP, USBDM, RESET, RSTOUT, PWREN,
+		      ADBUS, ACBUS, SI_WUA, BDBUS, BCBUS, SI_WUB);
+
+input GND, VCC, VCCIOA, VCCIOB;
+
+inout USBDP, USBDM;
+
+input RESET;
+output RSTOUT, PWREN;
+
+inout [7:0] ADBUS, BDBUS;
+inout [3:0] ACBUS, BCBUS;
+input SI_WUA, SI_WUB;
+
+/* FT2232D pins handled within this block */
+
+wire EECS, EESK, EEDATA;
+wire XTIN, XTOUT;
+wire AVCC, FTDI_3V3;
+
+/* instantiate the FT2232D */
+
+FT2232D_chip FT2232D   (.GND(GND),
+			.AGND(GND),
+			.VCC(VCC),
+			.AVCC(AVCC),
+			.VCCIOA(VCCIOA),
+			.VCCIOB(VCCIOB),
+			.OUT_3V3(FTDI_3V3),
+			.USBDP(USBDP),
+			.USBDM(USBDM),
+			.EECS(EECS),
+			.EESK(EESK),
+			.EEDATA(EEDATA),
+			.RESET(RESET),
+			.RSTOUT(RSTOUT),
+			.TEST(GND),
+			.PWREN(PWREN),
+			.XTIN(XTIN),
+			.XTOUT(XTOUT),
+			.ADBUS(ADBUS),
+			.ACBUS(ACBUS),
+			.SI_WUA(SI_WUA),
+			.BDBUS(BDBUS),
+			.BCBUS(BCBUS),
+			.SI_WUB(SI_WUB)
+	);
+
+/* VCCIO bypass caps */
+
+capacitor VCCIOA_bypass_cap (VCCIOA, GND);
+capacitor VCCIOB_bypass_cap (VCCIOB, GND);
+
+/* AVCC filter */
+
+resistor AVCC_filter_R (VCC, AVCC);
+capacitor AVCC_cap (AVCC, GND);
+
+/* 3V3OUT */
+
+capacitor FTDI_3V3_cap (FTDI_3V3, GND);
+
+/* crystal oscillator */
+
+xtal_2pin_pkg xtal (XTIN, XTOUT);
+capacitor XTIN_cap (XTIN, GND);
+capacitor XTOUT_cap (XTOUT, GND);
+
+/* serial EEPROM */
+
+wire EEPROM_DOUT;
+
+eeprom_93Cx6_16bit eeprom (.GND(GND),
+			   .VCC(VCC),
+			   .CS(EECS),
+			   .SK(EESK),
+			   .DIN(EEDATA),
+			   .DOUT(EEPROM_DOUT)
+	);
+
+resistor DOUT_series_R (EEPROM_DOUT, EEDATA);
+resistor DOUT_pullup_R (EEPROM_DOUT, VCC);
+
+endmodule