MAC7200 datasheet(642/976 Pages) FREESCALE

642 / 976 page

Functional Description

MAC7200 Microcontroller Family Reference Manual, Rev. 2

564

Freescale Semiconductor

29.6.2.8

Handshaking

The clock synchronization mechanism can be used as a handshake in data transfer. Slave devices may hold

the SCL low after completion of one byte transfer (9 bits). In such cases, it halts the bus clock and forces

the master clock into wait state until the slave releases the SCL line.

29.6.2.9

Clock Stretching

The clock synchronization mechanism can be used by slaves to slow down the bit rate of a transfer. After

the master has driven SCL low, the slave can drive SCL low for the required period and then release it. If

the slave SCL low period is greater than the master SCL low period then the resulting SCL bus signal low

period is stretched.

29.6.3

Interrupts

29.6.3.1

General

The I2C_DMA uses only one interrupt vector.

29.6.3.2

Interrupt Description

There are five types of internal interrupts in the I2C. The interrupt service routine can determine the

interrupt type by reading the Status Register.

I2C Interrupt can be generated on

•

Arbitration Lost condition (IBAL bit set)

•

Byte Transfer condition (TCF bit set and DMAEN bit not set)

•

Address Detect condition (IAAS bit set)

•

No Acknowledge from slave received when expected

•

Bus Going Idle (IBB bit not set)

The I2C interrupt is enabled by the IBIE bit in the I2C Control Register. It must be cleared by writing ‘1’

to the IBIF bit in the interrupt service routine. The Bus Going Idle interrupt needs to be additionaly enabled

by the BIIE bit in the IBIC register.

Table 29-11. Interrupt Summary

Interrupt

Offset

Vector Priority

Source

Description

I2C

Interrupt

———

IBAL, TCF,

IAAS, IBB bits in

IBSR register

When any of IBAL, TCF or IAAS bits is set an interrupt may

be caused based on Arbitration lost, Transfer Complete or

Address Detect conditions. If enabled by BIIE, the

deassertion of IBB can also cause an interrupt, indicating

that the bus is idle.

MAC7200 Datasheet(PDF) 642 Page - Freescale Semiconductor, Inc

MAC7200 Datasheet(HTML) 642 Page - Freescale Semiconductor, Inc

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 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL