The APC3 PROFIBUS DP ASIC is a communication controller designed for the development of intelligent PROFIBUS DP slave devices. It supports the DPV0 part of the PROFIBUS DP standard and provides a processor interface, dual-port RAM, status and interrupt functions, automatic baud-rate recognition, watchdog functions, and PROFIBUS DP service processing.
APC3 supports Intel and Motorola processor interface modes and provides an 8-bit data interface with an 11-bit address bus for access to its internal dual-port RAM. The device requires a 48 MHz external clock and can provide 24 MHz or 12 MHz clock output to an external processor.
PROFIBUS DP Slave Controller for Intelligent Devices
APC3 is designed specifically for the development of PROFIBUS DP intelligent slave stations.
The ASIC supports the DPV0 part of the PROFIBUS DP standard and provides the communication-related functions documented in the APC3 user manual. These include station address handling, parameterization, configuration checking, diagnostics, data exchange, input and output reading, and global control.
For device developers, APC3 provides the hardware interfaces and internal memory structure required to connect a processor with the PROFIBUS DP communication functions of the ASIC.
APC3 PROFIBUS DP ASIC Features
- PROFIBUS DP intelligent slave station development
- DPV0 support
- Intel and Motorola processor interface modes
- Synchronous and asynchronous 8-bit data interface
- 11-bit address bus
- 1.5K dual-port RAM
- 192 RAM segments of 8 bytes each
- Automatic baud-rate recognition from 9.6 kbps to 12 Mbps
- Status register and interrupt controller
- Watchdog and response-time monitoring
- PROFIBUS DP parameterization and configuration processing
- Diagnostic data processing
- 48 MHz external clock input
- 24 MHz / 12 MHz clock output to an external processor
- 44-pin PQFP package
- 3.3 V supply
PROFIBUS DPV0 Support
APC3 supports the DPV0 part of PROFIBUS DP.
The PROFIBUS-DP interface includes the following services:
| Service | Function |
|---|---|
| Set_Slave_Address (SAP55) | Slave station address setting |
| Set_Param (SAP61) | Parameterization data |
| Check_Config (SAP62) | Configuration checking |
| Slave_Diagnosis (SAP60) | Diagnostic information |
| Write_Read_Data / Data_Exchange | Data exchange |
| Global_Control (SAP58) | DP slave control commands |
| Read_Inputs (SAP56) | Reading input data |
| Read_Outputs (SAP57) | Reading output data |
| Get_Config (SAP59) | Reading configuration data |
The APC3 manual describes these DP services as part of its PROFIBUS-DP interface.
Processor Interface
APC3 supports both Intel and Motorola processor interface modes.
The interface mode is configured through the XINT/MOT and MODE pins. The processor can access the internal dual-port RAM through an 8-bit data interface and an 11-bit address bus.
The hardware design section of the manual defines four processor interface configurations:
| XINT/MOT | MODE | Processor Interface |
|---|---|---|
| 0 | 1 | Synchronous Intel mode |
| 0 | 0 | Asynchronous Intel mode |
| 1 | 0 | Asynchronous Motorola mode |
| 1 | 1 | Synchronous Motorola mode |
The APC3 manual also provides application examples using the 80C32 and 80C165 processors.
1.5K Dual-Port RAM
APC3 integrates 1.5K dual-port RAM, which is used as the interface between the ASIC and software.
The RAM is logically divided into 192 segments, with each segment containing 8 bytes. The memory structure includes processor parameters, organization parameters, DP data buffers, diagnostic buffers, parameter-setting data, and configuration data.
The DP buffer structure includes:
- Three Data In buffers
- Three Data Out buffers
- Two diagnostic buffers
- One parameter-setting data buffer
- Two configuration data buffers
The manual defines Data In as data transmitted from the PROFIBUS slave to the master and Data Out as data transmitted from the PROFIBUS master to the slave.
Automatic PROFIBUS DP Baud Rate Recognition
APC3 can automatically identify the PROFIBUS DP baud rate from 9.6 kbps to 12 Mbps.
The supported baud rates are:
- 12 Mbps
- 6 Mbps
- 3 Mbps
- 1.5 Mbps
- 500 kbps
- 187.5 kbps
- 93.75 kbps
- 45.45 kbps
- 19.2 kbps
- 9.6 kbps
After reset or a watchdog timeout, APC3 enters the baud-rate search state. It searches from the highest baud rate and continues to the next lower rate until a valid communication rate is identified.
After the baud rate has been identified, APC3 enters the Baud_Control state and continues monitoring the selected baud rate.
PROFIBUS DP Watchdog Monitoring
APC3 provides watchdog functions for communication monitoring.
The watchdog operates with a 100 Hz frequency, corresponding to a 10 ms time base. After receiving a valid message addressed to the device, the watchdog timer is reset. When the timer expires, APC3 returns to the baud-rate search state.
APC3 also supports response-time monitoring for the PROFIBUS DP master. The monitoring time range is 1 ms to 650 s, independent of baud rate. When the monitoring timer expires, APC3 returns to the Baud_Control state and generates a WD_DP_Control_Timeout interrupt event.
PROFIBUS DP Diagnostic Processing
APC3 provides status and diagnostic functions for the PROFIBUS DP slave.
The status register can provide information including:
- Offline / Passive-Idle state
- DP state
- Watchdog state
- Diagnostic flag
- RAM access violation
- Baud-rate status
These status values are available through the APC3 status register.
APC3 provides two diagnostic buffers for diagnostic data processing. One buffer can be used for APC3 diagnostic data transmission, while the other can be used by the user to prepare new diagnostic information.
PROFIBUS DP Parameterization
APC3 supports the Set_Param service for PROFIBUS DP parameterization.
The Class II master assigns communication parameters to the slave through the Set_Param service and specifies the operating status. The slave also receives the address of the master with which it is communicating.
Set_Param data contains standard parameters and user parameters. The manual states that user parameters are determined by the device manufacturer and described in the GSD file.
PROFIBUS DP Configuration Checking
APC3 supports the Check_Config service.
After parameterization, the master sends Check_Config messages that define the structure of the input and output data exchanged with the slave.
APC3 places the received configuration data into the Cfg buffer and generates a New_Cfg_Data interrupt for the user processor. The user processor then checks the configuration data and confirms the result.
PROFIBUS DP Slave Address
APC3 supports Set_Slave_Address (SAP55) for changing or configuring the slave station address.
The APC3 manual describes two methods for setting the address. A Class II master can modify the slave address through a service message, or a device can use a DIP switch and write the selected value to the APC3 station-address register.
When APC3 receives a valid Set_Slave_Address message, it stores the service data in its buffers and generates a New_SSA_Data interrupt.
PROFIBUS DP Data and Buffer Management
APC3 organizes PROFIBUS DP input and output data through dedicated buffers.
Each of the input and output data areas has three available buffers of the same length. These buffers are used as swap buffers between the DP communication process and the user side. The diagnostic section also contains two variable-length buffers.
The buffer organization supports the handling of Data In, Data Out, diagnostics, parameterization data, and configuration data within the internal RAM structure.
APC3 Clock Configuration
APC3 requires a 48 MHz external clock.
The ASIC can output a 24 MHz or 12 MHz clock to an external processor.
The hardware documentation specifies VDD as +3.3 V and VSS as 0 V. Different signal inputs use CMOS, CMOS Schmitt-trigger, CMOS pulldown, or TTL Schmitt-trigger levels depending on the pin function.
APC3 Pin Configuration
APC3 is housed in a 44-pin PQFP package.
The pinout includes processor interface signals, address and data lines, PROFIBUS interface signals, reset, interrupt, clock, and control pins. PROFIBUS interface-related signals include TXD, RTS, and RXD.
APC3 PROFIBUS DP ASIC Technical Specifications
| Parameter | Specification |
|---|---|
| Product | APC3 |
| Device type | PROFIBUS DP ASIC |
| Main application | Development of intelligent PROFIBUS DP slave stations |
| PROFIBUS function | DPV0 |
| Processor interface | Intel / Motorola |
| Data interface | 8-bit |
| Address bus | 11-bit |
| Internal RAM | 1.5K dual-port RAM |
| RAM organization | 192 segments × 8 bytes |
| External clock | 48 MHz |
| Clock output | 24 MHz / 12 MHz |
| Automatic baud-rate recognition | 9.6 kbps to 12 Mbps |
| Operating temperature | −40°C to +85°C |
| Storage temperature | −65°C to +150°C |
| Junction temperature | −40°C to +85°C |
| Supply voltage | 3.3 V |
| Package | 44-pin PQFP |
The specifications above are taken from the APC3 V2.2 user manual.
APC3 Application Examples
The APC3 hardware design section provides processor interface configurations and application examples.
The manual includes example designs for systems using the 80C32, an 80C32 system with external memory, an 80286 system in X86 mode, and an application using the 80C165.
APC3 Compatibility
The APC3 manual states that, at a 3.3 V operating voltage, APC3 is fully compatible with VPC3 operating in DPV0 mode. It also states that, apart from the different operating voltage, APC3 is fully compatible with SPC3 in DPV0 mode.
This compatibility statement is limited to the conditions and DPV0 mode specified in the manual.
FAQ
What is APC3?
APC3 is an ASIC designed for the development of intelligent PROFIBUS DP slave stations and supports the DPV0 part of the PROFIBUS DP standard.
What is a PROFIBUS DP ASIC?
A PROFIBUS DP ASIC is a dedicated integrated circuit used to implement PROFIBUS DP communication functions in a device. APC3 is specifically designed for developing intelligent PROFIBUS DP slave stations.
What baud rates does APC3 support?
APC3 automatically identifies PROFIBUS DP baud rates from 9.6 kbps to 12 Mbps, including 9.6, 19.2, 45.45, 93.75, 187.5, 500 kbps, 1.5, 3, 6, and 12 Mbps.
Does APC3 support Intel and Motorola processors?
Yes. APC3 supports both Intel and Motorola processor interface modes, configurable through the XINT/MOT and MODE pins.
How much RAM does APC3 have?
APC3 integrates 1.5K dual-port RAM, divided into 192 segments of 8 bytes each.
What PROFIBUS DP services does APC3 support?
The manual describes Set_Slave_Address, Set_Param, Check_Config, Slave_Diagnosis, Write_Read_Data / Data_Exchange, Global_Control, Read_Inputs, Read_Outputs, and Get_Config.
What package is APC3 available in?
APC3 uses a 44-pin PQFP package.
APC3 User Manual
For detailed information about processor interfaces, memory organization, registers, PROFIBUS DP services, watchdog operation, hardware configuration, and application examples, refer to the APC3 DP Fieldbus Communication Controller User Manual V2.2.
APC3 PROFIBUS DP Slave Controller
APC3 provides the PROFIBUS DP communication controller functions documented for intelligent slave station development, including DPV0 support, processor interfaces, dual-port RAM, automatic baud-rate recognition, diagnostics, parameterization, configuration checking, and PROFIBUS DP data exchange.
For technical information about the APC3 PROFIBUS DP ASIC, please contact Microcyber.
