MAXQ2010-RFX+ datasheet(26/34 Pages) MAXIM

26 / 34 page

16-Bit Mixed-Signal Microcontroller

with LCD Interface

______________________________________________________________________________________

The time base of the serial ports is derived from either a

division of the system clock or the dedicated baud-

clock generator. Table 1 summarizes the operating

characteristics of each mode.

I2C Bus

The microcontroller integrates an internal I2C bus mas-

ter/slave for communication with a wide variety of other

I2C-enabled peripherals. The I2C bus is a 2-wire bidi-

rectional bus using two bus lines, the serial data line

(SDA), and the serial clock line (SCL), as well as a

ground line. Both the SDA and SCL lines must be dri-

ven as open-collector/drain outputs. External resistors

are required as shown in Figure 3 to pull the lines to a

logic-high state.

The MAXQ2010 is flexible in that it supports both the

master and slave protocols. In the master mode, the

device has ownership of the I2C bus and drives the

clock and generates the START and STOP signals. This

allows it to send data to a slave or receive data from a

slave as required. In slave mode, the MAXQ2010 relies

on an externally generated clock to drive SCL and

responds to data and commands only when requested

by the I2C master device.

Serial Peripheral Interface (SPI)

The integrated SPI provides an independent serial

communication channel that communicates synchro-

nously with peripheral devices in a multiple master or

multiple slave system. The interface allows access to a

4-wire, full-duplex serial bus, and can be operated in

either master mode or slave mode. Collision detection

is provided when two or more masters attempt a data

transfer at the same time.

The maximum SPI master transfer rate is Sysclk/2.

When operating as an SPI slave, the MAXQ2010 can

support up to a Sysclk/4 SPI transfer rate. Data is trans-

ferred as an 8-bit or 16-bit value, MSB first. In addition,

the SPI module supports configuration of active SSEL

state through the slave-active select.

Real-Time Clock

A binary real-time clock (RTC) keeps the time of day in

absolute seconds with 1/256-second resolution. The

32-bit second counter can count up to approximately

136 years and be translated to calendar format by

application software. A time-of-day alarm and indepen-

dent subsecond alarm can cause an interrupt or wake

the device from stop mode.

The independent subsecond alarm runs from the same

RTC and allows the application to support interrupts

with a minimum interval of approximately 3.9ms. This

creates an additional timer that can be used to mea-

sure long periods of time without performance degra-

dation. Traditionally, long time periods have been

measured using multiple interrupts from shorter inter-

rupt intervals. Each timer interrupt required servicing,

with each accompanying interruption slowing system

operation. By using the RTC subsecond timer as a

long-period timer, only one interrupt is needed, elimi-

nating the performance hit associated with using a

shorter timer.

An internal crystal oscillator clocks the RTC using inte-

grated 6pF load capacitors, and yields the best perfor-

mance when mated with a 32.768kHz crystal rated for a

6pF load. No external load capacitors are required.

Higher accuracy can be obtained by supplying an

external clock source to the RTC.

Programmable Timers

The microcontroller incorporates three instances of the

16-bit programmable Timer/Counter B peripheral,

denoted TB0, TB1, and TB2. They can be used in

counter/timer/capture/compare/PWM functions, allow-

ing precise control of internal and external events.

These timer/counters support clock input prescaling

and set/reset/toggle PWM/output control functionality

not found on other MAXQ timer implementations. A new

functions in some implementations. A distinguishing

characteristic of Timer/Counter B is that its count

MODE

TYPE

START BITS

DATA BITS

STOP BIT

Mode 0

Synchronous

—

Mode 1

Asynchronous

Mode 2

Asynchronous

8 + 1

Mode 3

Asynchronous

8 + 1

Table 1. Serial Port Operating Characteristics

MAXQ2010-RFX+ Datasheet(PDF) 26 Page - Maxim Integrated Products

MAXQ2010-RFX+ Datasheet(HTML) 26 Page - Maxim Integrated Products

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

Datasheet Download

Link URL