UM0193

Hardware

9/35

Figure 10.

JTAG schematic diagram

1.6.1

JTAG supply voltages

A +3.3V DC supply voltage placed on pins 1 and 2 is provided by the DC/DC converter (U6)

reference pin or a separate linear voltage regulator (U7). Please verify the consumption of

any device (for example, converter box) connected to this connector. According to the

device datasheet, the reference pin can deliver a maximum current of 5mA, providing an

accurate voltage level. If the consumption is higher, select the linear voltage regulator (U7)

for the supply connector using jumper J33 as described in Appendix C: Jumper settings.

Certain converter boxes provide a +5V DC supply voltage for the JTAG interface. The new

generation J-link from IAR Systems (the yellow one) provides the supply voltage on pin

number 19. For applications using supplies from the converter box, connect a wire from pin

number 19 of the JTAG (J7) connector to closest +5V DC supply point (for example, J19

right pin). For JTAG communication functions, jumper J32 must be connected and jumper

J33 set to the "lin" position when a +5V DC voltage supply is used.

Caution:

Using a supply from a converter box is not recommended for application development or

testing. Accidental short-circuits may damage USB host or converter box circuits.

Table 7.

JTAG connections

Pin

Signal

Pin

Signal

1

+3.3V DC

2

+3.3V DC

3JTRST

4

GND

5JTDI

6

GND

7JTMS

8

GND

9JTCK

10

GND

11

Connected to GND by R18 (10k

GND

13

JTDO

14

GND

15

RESET

16

GND

17

Connected to GND by R20 (10k

GND

19

Connected to GND by R21 (10k

GND

Ai11699

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

3V3

3V3

3V3

3V3

3V3

3V3

3V3

3V3

C51

100 nF

3V3

C18

100 nF

3V3

C52

10M/16V

+

CON20A

3V3

J7

R18

10k

R19

10k

R20

10k

R21

10k

D2

BZX84C3V3/SOT

R17 430R

nJTRST

JTDI

JTMS

JTCK

JTDO

nRST_EXT

R11

10k

NA

R12

10k

R13

10k

R14

10k

R15

10k

NA

R16

10k

NA