Modem 9k6 de G4XYW (english)

Modem 9k6 of G4XYW (circuit modified v1.0)

The modem of G4XYW uses a AT90S1200 from Atmel, it is possible to work in full-duplex by adding a second circuit which deals exclusively with decoding Rx.
It is also possible to interface this modem with Tnc (dated Tx/Rx in NRZI), a port series (mode ASY) or a Scc card (Atepra or Baycom).
Several options of software are available with jumpers.
See the site of G4GYW for the software of the AT90S1200 and the drivers, the site of BA1FB to program it via the parallel port.

Should be used referred Atmel circuits: AT90s1200-12PC (12Mhz version) it is available Radiospares. (France)

The tests are in progress for the Tnc mode

Files:

List of components (pdf format)
The printed circuit in GIF (pcb, component view, straps)
The printed circuit in Postscript (pcb, component view, straps)
The printed circuit in pdf format (Use Acrobat Reader 4, do not use 'Ajust' option in a printer setup)

The circuit:

It is a simple face of dimensions 100 X 130mm.

Printed circuit of the modem

Component view

List of components
Value	Reference	Config	Remarks
AT90S1200	IC1		(shifted of one 1/2 case with IC5 in full-duplex)
74HCT14	IC2
LM393	IC3
CA324	IC4
AT90S1200	IC5	Full	Only in Full-duplex
MAX232	IC6	ASY	Only on port series (ASY)
78L05 / 7805	IC7		Regulator 5v
9.8304MHZ	X1
NPN	TR1
Jumpers
L1	L1		Jumper: CW ON/OFF
L2	L2	Full	Jumper: Tx PLL ON/OFF (sending Clock Tx in Full-duplex)
L3	L3		Jumper: mode ASY (max232)
L4	L4		Jumper: Tx mode (see back)
L5	L5		Jumper: Tx mode (see back)
L6	L6	Full	Jumper: invert Clock Tx (full)
L7	L7		disable watchdog
L9-10	L9-10		Jumper: invert DCD
L11	L11	Full	Jumper: invert Clock Rx (full)

L4	L5	Mode
Not	Not	Raised cosine (default)
Not	Yes	GMSK
Yes	Not	sinx/x compensated cosine
Yes	Yes	Raised cosine (default)

T1	T1		Test Rx eyes
T4	T4		Test Tx eyes

LED	DCD1		Led Dcd
4µ7	C1		Radial chemical condenser
18pF	C2		Ceramic condenser 2,54
18pF	C3		Ceramic condenser 2,54
1µF	C4		Radial chemical condenser
100nF	C6		Condenser polyester
220pF	C7		Ceramic condenser 5,08
100pF	C8		Ceramic condenser 5,08
10µF	C9		Radial chemical condenser
220pF	C10		Ceramic condenser 5,08
470pF	C11		Ceramic condenser 5,08
100nF	C12		Condenser polyester
100nF	C13		Condenser polyester
10µF	C14		Radial chemical condenser
1µF	C15		Radial chemical condenser
100nF	C17		Condenser polyester
100nF	C18		Condenser polyester
100nF	C19		Condenser polyester
10µF	C31	ASY	Radial chemical condenser
10µF	C32	ASY	Radial chemical condenser
10µF	C33	ASY	Radial chemical condenser

1N4148	D1		Diode
1N4148	D2		Diode
1N4148	D3		Diode
1N4148	D4		Diode
1N4148	D5		Diode
1N4148	D6		Diode
1N4148	D7		Diode
1N4148	D8	Full	Diode
1N4007	D9		Diode of protection (optional)
DZ33V	D10		Diode Zener 33Volts (optional)

2K2	R1		Resistance 1/4 W
3M3	R2		Resistance 1/4 W
470	R3		Resistance 1/4 W
680	R4		Resistance 1/4 W
470	R5		Resistance 1/4 W
2K2	R6		Resistance 1/4 W
10K	R7		Resistance 1/4 W
10K	R8		Resistance 1/4 W
10K	R9		Resistance 1/4 W
10K	R10		Resistance 1/4 W
10K	R11		Resistance 1/4 W
10K	R12		Resistance 1/4 W
10K	R13		Resistance 1/4 W
10K	R14		Resistance 1/4 W
5K1	R15		Resistance 1/4 W
5K1	R16		Resistance 1/4 W
10K	R17		Resistance 1/4 W
5K1	R18		Resistance 1/4 W
5K1	R19		Resistance 1/4 W
10K	R20		Resistance 1/4 W
1M	R21		Resistance 1/4 W
560	R22		Resistance 1/4 W
100K	R23		Resistance 1/4 W
100K	R24		Resistance 1/4 W
100K	R26		Resistance 1/4 W
56K	R25		Resistance 1/4 W
100K	R27		Resistance 1/4 W
10K	R28		Resistance 1/4 W
10K	R29		Resistance 1/4 W
220K	R30		Resistance 1/4 W
39K	R31		Resistance 1/4 W
82K	R32		Resistance 1/4 W
470	R33		Resistance 1/4 W
10KLIN	RV1		Adjustable multi-turn horizontal

12V	ALIM1		Connector alim 12V
SCC	SK2		Connector DB9-Female
SK1	SK1	TNC	Connector Tnc
TRX	SK3		Base DIN 5pin/180°

Straps:

Location of the straps on the circuit

Mode

Str 1

Str 2

Str 3

Str 4

Str 5

Str 6

Str 7

Str 8

Str 9

Str 10

Str 11

Str 12

Str 13

Str 14

Tnc Half-Duplex

Asy Half-Duplex

Scc Half-Duplex

Scc Full-Duplex

Tnc Full-Duplex

Full-duplex mode, sending of Tx Clock

Tx PLL is disabled with the jumper L2, circuit IC1 is blocked in Tx by strap13 and sends the clock Tx Clock.
The clock Tx Clock use a gate of IC2 (pin1/2) which is used in the beginning to commutate the µP in Tx/Rx.
It is necessary to cut two wires, to put a strap of welding and to come out the clock on the DB9 (pin6) or the Tnc connector
Two clocks (Tx and Rx) can be inverted with the jumpers L6 and L11 if needed.
In the case of the use of Scc4 Atepra it is necessary to make some modifications on the card controller by using the free gates buffers (U3E, F, G, H) to send the clock signals on Z8530 (remove the dividing circuit 4024)

In Half-duplex mode Scc card work in dpll mode it does not have there a clock to send on the z8530.

Stitching of the connectors

Female DB9 for Scc4 Atepra	Connector DIN 5 pins (standard baycom)
1: DCD	1: data Tx (Micro)
2: Rxd	2: Ground
3: Txd	3: Ptt
4: NC (12v)	4: Data Rx (HP)
5: Gnd	5: NC
6: Clock Tx
7: RTS	NC = Off-line
8: CTS
9: Clock Rx

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