C8051F320DK Silicon Laboratories Inc, C8051F320DK Datasheet - Page 172

• Manufacturer Part Number: C8051F320DK
• Description: DEV KIT FOR C8051F320/F321
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F320DK

• Contents: Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
• Processor To Be Evaluated: C8051F320/F321
• Interface Type: USB
• Silicon Manufacturer: Silicon Labs
• Core Architecture: 8051
• Silicon Core Number: C8051F320
• Silicon Family Name: C8051F32x
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Silicon Laboratories C8051F320, C8051F321
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1260

C8051F320/1
16.3.4. SCL High (SMBus Free) Timeout
The SMBus specification stipulates that if the SCL and SDA lines remain high for more that 50 µs, the bus
is designated as free. When the SMBFTE bit in SMB0CF is set, the bus will be considered free if SCL and
SDA remain high for more than 10 SMBus clock source periods. If the SMBus is waiting to generate a
Master START, the START will be generated following this timeout. Note that a clock source is required for
free timeout detection, even in a slave-only implementation.
16.4. Using the SMBus
The SMBus can operate in both Master and Slave modes. The interface provides timing and shifting con-
trol for serial transfers; higher level protocol is determined by user software. The SMBus interface provides
the following application-independent features:
•
•
•
•
•
•
•
SMBus interrupts are generated for each data byte or slave address that is transferred. When transmitting,
this interrupt is generated after the ACK cycle so that software may read the received ACK value; when
receiving data, this interrupt is generated before the ACK cycle so that software may define the outgoing
ACK value. See Section “16.5. SMBus Transfer Modes” on page 180 for more details on transmission
sequences.
Interrupts are also generated to indicate the beginning of a transfer when a master (START generated), or
the end of a transfer when a slave (STOP detected). Software should read the SMB0CN (SMBus Control
register) to find the cause of the SMBus interrupt. The SMB0CN register is described in Section
“16.4.2. SMB0CN Control Register” on page 176; Table 16.4 provides a quick SMB0CN decoding refer-
ence.
SMBus configuration options include:
•
•
•
•
These options are selected in the SMB0CF register, as described in Section “16.4.1. SMBus Configuration
Register” on page 173.
172
Byte-wise serial data transfers
Clock signal generation on SCL (Master Mode only) and SDA data synchronization
Timeout/bus error recognition, as defined by the SMB0CF configuration register
START/STOP timing, detection, and generation
Bus arbitration
Interrupt generation
Status information
Timeout detection (SCL Low Timeout and/or Bus Free Timeout)
SDA setup and hold time extensions
Slave event enable/disable
Clock source selection
Rev. 1.4