工具与软件：
您好！
我在没有操作系统的情况下运行 TMDS64EVM。
问题、关于实时计数器时钟。 
我正在从 A9000C 读取 高位、从 A90008读取低位。
问题：
1.
highbits + low bits 将是 CPU 周期对吧？ 例如：我具有十进制的高值0和低值200
这意味着 CPU 在当前时间内有200个周期在运行。 是这样吗。
2.在800MHz 系统中、每个 CPU 周期应有1.25毫微/秒的性能？
而是每个 CPU 周期2纳秒。 我得到低值,让系统运行500毫秒,并得到低值, 我发现它需要 25万000 ,这意味着我的 CPU 运行2纳秒/每周期
那么、 问题可能出在哪呢？ GTC 寄存器设置中有什么内容吗、我设置不正确？
谢谢。
您好！
我希望您通读以下 E2E。
我来自客户曾使用 AM64x 的另一个论坛的其中一个回复：
"
是的、GTC 应从它拥有的最后一个计数值开始继续运行(即使在 JTAG 复位时也是如此)。 这在 AM64x TRM 中提到、我已附加一个片段。 如果您详细了解一下、那会很有帮助。
此外、我认为您需要在软复位时将 GTC 计数器值重置为零、因此我编写了一个小应用程序、在 JTAG 复位+运行应用程序后会执行相同的操作。
在上面的屏幕截图中、我已经实现了4个步骤、我建议您使用随附 C 文件中提到的流程来将计数器值重置为0。
/*
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#include <stdio.h>
#include <kernel/dpl/DebugP.h>
#include <inttypes.h>
#include "ti_drivers_config.h"
#include "ti_drivers_open_close.h"
#include "ti_board_open_close.h"
#include <drivers/gtc.h>
#include <drivers/soc.h>
#include <drivers/gtc/v0/cslr_gtc.h>
#include <kernel/dpl/ClockP.h>
/*
* This is an empty project provided for all cores present in the device.
* User can use this project to start their application by adding more SysConfig modules.
*
* This application does driver and board init and just prints the pass string on the console.
* In case of the main core, the print is redirected to the UART console.
* For all other cores, CCS prints are used.
*/
void GTC_disable(void);
void GTC_clearCountRegisters(void);
void hello_world_main(void *args)
{
int32_t retVal = SystemP_SUCCESS;
uint64_t gtcCount1 = 0, gtcCount2 = 0;
uint64_t clkRate = 0;
/* Open drivers to open the UART driver for console */
Drivers_open();
Board_driversOpen();
// This API is called to reset the 0th and 1st bit of the GTC0_GTC_CFG1_GTC_CFG1_CNTCR register
GTC_disable();
// Now clear the GTC0_GTC_CFG1_GTC_CFG1_CNTCV_LO and GTC0_GTC_CFG1_GTC_CFG1_CNTCV_HI registers
GTC_clearCountRegisters();
retVal = GTC_init();
DebugP_assert(SystemP_SUCCESS == retVal);
retVal = SOC_moduleGetClockFrequency(TISCI_DEV_GTC0, TISCI_DEV_GTC0_GTC_CLK, &clkRate);
DebugP_assert(SystemP_SUCCESS == retVal);
gtcCount1 = GTC_getCount64();
ClockP_sleep(3);
gtcCount2 = GTC_getCount64();
DebugP_log("%lf is the time taken in seconds for testing GTC!!!\r\n",((Float64)((Float64)gtcCount2 - (Float64)gtcCount1) / (Float64)clkRate));
Board_driversClose();
Drivers_close();
}
void GTC_disable(void)
{
uint32_t baseAddr = (uint32_t) AddrTranslateP_getLocalAddr(CSL_GTC0_GTC_CFG1_BASE);
HW_WR_REG32(baseAddr, 0);
return;
}
void GTC_clearCountRegisters(void)
{
uint32_t baseAddr = (uint32_t) AddrTranslateP_getLocalAddr(CSL_GTC0_GTC_CFG1_BASE);
HW_WR_REG32(baseAddr + CSL_GTC_CFG1_CNTCV_LO, 0); // Firstly, setting LO to 0
HW_WR_REG32(baseAddr + CSL_GTC_CFG1_CNTCV_HI, 0); // Secondly, setting HI to 0
return;
}
"
此致、
Vaibhav