DEMO9S12XEP100 Freescale Semiconductor, DEMO9S12XEP100 Datasheet - Page 599

• Manufacturer Part Number: DEMO9S12XEP100
• Description: BOARD DEMO FOR MC9S12XEP100
• Manufacturer: Freescale Semiconductor
• Type: MCUr

Specifications of DEMO9S12XEP100

• Contents: Board, Cables, CD
• Processor To Be Evaluated: MC9S12XEP100
• Data Bus Width: 16 bit
• Interface Type: RS-232
• Silicon Manufacturer: Freescale
• Core Architecture: S12
• Core Sub-architecture: S12
• Silicon Core Number: MC9S12
• Silicon Family Name: S12XE
• Rohs Compliant: Yes
• For Use With/related Products: MC9S12XEP100
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

15.4.1.8
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 case, it halts the bus clock and forces
the master clock into wait states until the slave releases the SCL line.
15.4.1.9
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.
15.4.1.10 Ten-bit Address
A ten-bit address is indicated if the first 5 bits of the first address byte are 0x11110. The following rules
apply to the first address byte.
The address type is identified by ADTYPE. When ADTYPE is 0, 7-bit address is applied. Reversely, the
address is 10-bit address.Generally, there are two cases of 10-bit address.See the Fig.1-14 and 1-15.
In the figure 1-15,the first two bytes are the similar to figure1-14.After the repeated START(Sr),the first
slave address is transmitted again, but the R/W is 1, meaning that the slave is acted as a transmitter.
15.4.1.11 General Call Address
To broadcast using a general call, a device must first generate the general call address($00), then after
receiving acknowledge, it must transmit data.
In communication, as a slave device, provided the GCEN is asserted, a device acknowledges the broadcast
and receives data until the GCEN is disabled or the master device releases the bus or generates a new
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S
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11110+ADR10+ADR9
Slave Add1st 7bits
Figure 15-13. A master-transmitter addresses a slave-receiver with a 10-bit address
Figure 15-14. A master-receiver addresses a slave-transmitter with a 10-bit address
Handshaking
Clock Stretching
S
ADDRESS
11110+ADR10+ADR9
11111XX
11110XX
0000000
0000010
0000011
SLAVE
Slave Add1st 7bits
R/W
0
Table 15-11. Definition of Bits in the First Byte
A1
MC9S12XE-Family Reference Manual Rev. 1.23
Slave Add 2nd byte
ADR[8:1]
R/W
R/W BIT
0
0
x
x
x
x
A1
A2
Slave Add 2nd byte
Chapter 15 Inter-Integrated Circuit (IICV3) Block Description
ADR[8:1]
Sr
Reserved for different bus format
Reserved for future purposes
Reserved for future purposes
11110+ADR10+ADR9
10-bit slave addressing
Slave Add 1st 7bits
General call address
DESCRIPTION
A2
Data
R/W
1
A3
A3
Data
A4
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