Instrustar ISDS205A

Instrustar ISDS205A

Status	in progress
Channels	2
Samplerate	48MHz
Analog bandwidth	20MHz
Vertical resolution	8bit
Triggers	none (SW-only)
Input impedance	1MΩ‖25pF
Memory	none
Display	none
Connectivity	USB
Website	instrustar.com

The Instrustar ISDS205A is a USB-based, 2-channel oscilloscope with an analog bandwidth of 20MS/s and 48MS/s sampling rate. Compared to products similar for boxing and price level it could be considered an enhanced version of FX2 oscilloscope, not in the boxing which appear to use worse materials, but in the hardware which allow a wider input range (from 0.09mVp to 6Vp) and an hardware AC/DC selector.

See Instrustar ISDS205A/Info for more details (such as lsusb -v output) on the device.

Hardware

• Cypress FX2LP CY7C68013AC (USB 2.0 HS controller)
• Analog Devices AD9288 (ADC)
• Microchip 24LC64I (64K I²C EEPROM)
• (2)NXP 74HC4051 (8-Channel Analog Mux)
• NXP 74HC595D (8bit Shift Register (Serial-in to Serial or Parallel-out)) (datasheet)
• Oscillator GZX24.000 (24MHz crystal)
• (4) Huike (Shenzhen) HK23F-DC5V-SHG (Reed switch)

Cypress FX2 pinout:

PD5	1-	O	-56	PD4
PD6	2-		-55	PD3
PD7	3-		-54	PD2
GND	4-		-53	PD1
CLKOUT	5-		-52	PD0
VCC	6-		-51	*WAKEUP
GND	7-		-50	VCC
RDY0/*SLRD	8-		-49	RESET#
RDY1/*SLWR	9-		-48	GND
AVCC	10-		-47	PA7
(24MHz crystal) XTALOUT	11-		-46	PA6 (74HC595D, SHCP)
(24MHz crystal) XTALIN	12-		-45	PA5 (74HC595D, STCP)
AGND	13-		-44	PA4 (74HC595D, DS)
AVCC	14-		-43	PA3
(USB D+) DPLUS	15-		-42	PA2
(USB D-) DMINUS	16-		-41	PA1
AGND	17-		-40	PA0 (1kHz scope cal pin)
VCC	18-		-39	VCC
GND	19-		-38	CTL2
(CTL0, AD9288 ENCA/B) *IFCLK	20-		-37	CTL1
RESERVED	21-		-36	CTL0 (IFCLK, AD9288 ENCA/B)
(EEPROM SCL) SCL	22-		-35	GND
(EEPROM SDA) SDA	23-		-34	VCC
VCC	24-		-33	GND
PB0	25-		-32	PB7
PB1	26-		-31	PB6
PB2	27-		-30	PB5
PB3	28-		-29	PB4

NXP 74HC595D pinout:

(upper 74HC4051D, S0) Q1	1-	O	-16	VCC
(lower 74HC4051D, S0) Q2	2-		-15	Q0 (upper 74HC4051D, S1)
(lower 74HC4051D, S1) Q3	3-		-14	DS (FX2 PA4)
CH2 low voltage relay Q4	4-		-13	OE# (GND)
CH2 AC/DC relay Q5	5-		-12	STCP (FX2 PA5)
CH1 low voltage relay Q6	6-		-11	SHCP (FX2 PA6)
CH1 AC/DC relay Q7	7-		-10	MR# (VCC)
GND	8-		-9	Q7S

NXP 74HC4051D (upper/lower, CH1/CH2) pinout:

Y4 1-   O -16 VCC Y6 2- -15 Y2 Z 3- -14 Y1 Y7 4- -13 Y0 Y5 5- -12 Y3 (GND) E# 6- -11 S0 (NXP 74HC595D, Q1) VEE 7- -10 S1 (NXP 74HC595D, Q0) GND 8- -9 S2 (GND)

Y4 1-   O -16 VCC Y6 2- -15 Y2 Z 3- -14 Y1 Y7 4- -13 Y0 Y5 5- -12 Y3 (GND) E# 6- -11 S0 (NXP 74HC595D, Q2) VEE 7- -10 S1 (NXP 74HC595D, Q3) GND 8- -9 S2 (GND)

Microchip 24LC64I pinout:

(VCC) A0	1-	O	-8	VCC
(GND) A1	2-		-7	WP (GND)
(GND) A2	3-		-6	SCL (FX2 SCL)
VSS	4-		-5	SDA (FX2 SDA)

Analog Devices ADS9288 pinout:

AD9288 pins	Description
S1, S2	S1=VCC, S2=GND. "Normal operation, data align disabled".
DFS	Tied to GND. Data format select = "offset binary" (not "twos complement").
AINA, AINB	Analog input channels.
D0A-D7A	Connected to FX2 PB0-PB7.
D0B-D7B	Connected to FX2 PD0-PD7.

Firmware

Note: The firmware is flashed into the device permanently.

EEPROM layout

The device has a 8KB I²C EEPROM with the following layout:

c2 47 05 31 21 00 00 04 XX XX XX XX XX XX .. ..

Description:

Bytes	Description
0	0xc2: FX2 "c2 load" mode, i.e. VID/PID/DID are loaded from EEPROM as the firmware.
1-2	0x0547: USB vendor ID (VID before firmware renumerate).
3-4	0x2131: USB product ID (PID before firmware renumerate).
5-6	0x0000: USB device ID (DID before firmware renumerate).
7	0x04: FX2 configuration byte (see FX2 TRM for details).
8-1917h	Firmware.
1918h -1fffh	All-0xff.

Photos

• 

  Device, top

• 

  Device, bottom

• 

  PCB, top

• 

  PCB, bottom

• 

  2x mux, ADC, shift-reg

• 

  (1 of 2) mux, ADC, shift-reg, USB, EEPROM, crystal

• 

  Jacks, reed switches, calibration. 2x mux, ADC, USB, crystal

Resources

• Aliexpress page
• User Guide
• SDK 2.6