The Eltron Company P310 manual USB Port Circuitry Optional

CHAPTER 3

3.4.5 USB Port Circuitry (Optional)

Figure 3-7 shows the USB circuitry. This circuitry resides on a separate board that attaches to the same connector that the Magnetic Stripe Encoder Connector can use. For configurations that have both the USB Board and a Magnetic Stripe Encoder, this board supplies a connector (J1) that carries through the connector signals. J1 resides just above the non-USB connection point.

The USB Chip (U2) includes hard wired programming that deals with the USB Protocols. Additionally, the chip has four FIFOs, or Endpoint Registers. One register is initialized with data characterizing the requirements of the Card Printer. The Host accesses this register to supply Address Data. A FIFO is designated as a Data Register.

The CPU Board accesses the Board through the CS SUP, R_W/, and A0 lines. Data between devices travels over the D+ and D- lines. When the FIFO designated for data reception reaches full status, U2 activates the IRQ4 line, an Interrupt Input to the Micro Controller. Note that the D+ and D- line are not differential. USB devices support bi-directional data flows.

J1

USB BOARD

J2		CS_SUP		U2
1			/CS		Magnetic
.		R_W/
	D16~D31		/RD		Stripe
.
		IRQ4	/WR		Encoder
.
			INT		Connection
18	R_W/
		10k	DRQ
19	CS_MAG	Vcc	/DACK
20						J3
21	RESET/	A0			0.35	1
	OUTPUT		A0
22	EXT2			D –		2
23	REFERENCE		D0	D+	0.35	3
24	IRQ4		D1		22pF 22pF	4
25	E ENCOD		D2
26	A1	D24~D31	D3		1.3k
27	A0		D4
28	CS_SUP		D5
29	EXT3		D6
30	GND		D7		10nF 10nF
31	Vdd	RESET/
32	GND		/RST	3.3V
33	Vdd		MODE0	AGND
34			MODE1
		U3	CLKOUT
		CLK	XIN
		24MHz
		Clock	XOUT

CPU Board

Micro Controller

Signals

Figure 3-7. USB Port Circuitry.

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