Eurotech BitsyXb, Руководство пользователя

Страница: 60 / 67

BitsyXb - User Manual
60 110118-0001A
6.3.6 ADSmartIO Controller
The ADSmartIO Controller is a second RISC microcontroller on the BitsyXb designed to handle
I/O functions autonomously. The BitsyXb communicates with the ADSmartIO controller using
the PXA270 SPI bus. On the BitsyXb, ADSmartIO is implemented with the Atmel
ATMEGA8535 microcontroller, which has 512 bytes EEPROM.
Absolute Maximum Ratings
Input voltage, any pin ................................................3.8 V
Symbol Parameter Min Typ. Max Units
Vdd ADSmartIO supply voltage 3.3 V
Rs Series resistance (note 21) 1
k Ω
Vprot (note 21) V
Digital Outputs (4.3.3)
Vol 0.5 V
Voh 2.3 3.3 V
I sink (see notes 21) 20 mA
I source (see notes 21) 12 mA
Digital Inputs (4.3.3)
Vih 0.6 Vdd
Vil 0.3 Vdd
R
Software-selectable pull-ups to 3.3 V
(see note 23)
35 120
k Ω
A/D Inputs (4.3.4)
n resolution (note 24) 8 10 bit
Rin 100
M Ω
Vref A/D reference voltage (note 25) 2.5 V
Ivref Current drain from ref voltage 100 uA
Vin valid A/D input voltage range 0 Vref V
I (Vref) J10.43 100
µ A
Temperature Sensing (4.3.5)
Rth external thermistor resistance @ 25C 33
k Ω
Vt thermistor excitation voltage Vref V
Rtl lower voltage divider 47
k Ω
I2C Bus (4.5.4, note 26)
Bus clock 50 kHz
input buffer size 32 byte
packet size 32 byte
Vi/o I/O voltages see digital I/Os, above V
Rbus
pull-up on SDA, SCK
4.7 k Ω
Vbus 3.3 V
Notes:
21. Row I/O, column I/O and SMTIO 0-1 have series resistance and overvoltage protection to
ground. The series resistance limits the dc current that any one pin can source or sink.
22. Control pull-up resistors by writing to bits of IO port when the port is configured as a digital
input (bit mask 1=enable, 0=disable).
23. Digital noise on the board may degrade analog performance under some conditions.
24. Vref turns off when the system is in Sleep mode (section 5.3.2).
25. Specifications based on ADSmartIO release 1010 rev 2 (Eurotech release #700114-10102)